Find the conjugate of 2 - 5i and then calculate the product of the given complex number and its conjugate. (1 point)

Answers

Answer 1

Answer:

29

Step-by-step explanation:

conjugate of a+ib=a-ib

conjugate of 2-5i=2+5i

(2+5i)(2-5i)=2²-(5i)²=4-25i²=4-25(-1)=4+25=29

Answer 2

Answer:

29

i had the same question and 29 was the right answer


Related Questions

|10-11| = simplify the expression

Answers

Answer:

1

Step-by-step explanation:

Let's ignore the absolute value signs for a moment.

We have the expression [tex]10-11[/tex]. We know that if we subtract 10 from 10 we get 0, so if we subtract 11 from 10 we must get -1.

However, there is an absolute value sign. This means that whatever number is inside it has to be converted to a positive number.

-1 as a positive number is +1, or just 1.

Hope this helped!

A caterer needs to know the volume of the remaining cake to determine how many servings she has. What is the volume of the remaining cake?

Answers

Answer: D. 288 in^3

Explanation:

To find volume of the remaining shape:

V (remaining) = V (original shape) - V (taken)

Find Volume of the original shape:

V(original) = 16 x 6 x 4 = 384 in^3

Find the volume of the taken shape:

V(taken) = 8 x 4 x 3 = 96 in^3

Find the volume of the remaining shape:

V (remaining) = 384 - 96 = 288in^3



Step-by-step explanation:

Hello, there!!!

Let's simply work with it,

Firslty let's assume the whole cake, when you assume the cake in whole. you get,

length (l)= 16 in

breadth (d)= 6 in

and height (h)= 4 in

now, as it is a rectangle shaped cake,

volume of a whole cake (v)= l×b×h

or, v= 16 in × 6 in × 4 in.

Therefore, the volume of whole cake is 384 cubic inch.

now,

let's find the volume of eaten part,

As per the picture, the 1/4th part of cake is eaten so,

length = 8 in

breadth = 3in

and height = 4in.

so, volume of eaten part = l × b × h

v= 8in × 3in × 4in

Therefore , v= 96 cubic inch.

now, lastly finding the volume of remaining part,

v. of remaining part = v.of whole cake - v. of eaten part.

or, v. of remaining part = 384 in^3 - 96 in^3

Therefore, the volume of remaining part is 288in^3.

Hope it helps....

A file that is 276 megabytes is being dowloaded. If 16.7% complete how many megabytes have been dowloaded? Round your answer to the nearest tenth

Answers

Answer:

30.9 mb

Step-by-step explanation:

Flaming BBQ restaurant makes a dipping sauce with 9 mL of hot sauce for every 6 ounces of barbecue sauce. Which of the following mixtures will taste the same as flaming BBQ's dipping sauce?
Choose 3 answers:
A. 6 mL of hot sauce mixed with 20 oz of barbecue sauce
B. 3 mL of hot sauce mixed with 2 oz of barbecue sauce
C. 45 mL of hot sauce mixed with 30 oz of barbecue sauce
D. 24 mL of hot sauce mixed with 18 oz of barbecue sauce
E. 12 mL of hot sauce mixed with 8 oz of barbecue sauce

pls help me ;-;​

Answers

Answer:

B, C , and E

Step-by-step explanation:

for 9 ml of hot sauce (x) +6 ounces of BBQ sauce(y)= flaming BBQ(c)

9x+6y=c

B: 3x+2y will give the same taste ( the quantity reduced to one third)

C: 45x+30y will give the same taste ( the quantity multiply by 5)

E:12 x+8y will give the same taste ( the quantity multiplied by 0.75)

I NEED HELP!! which expression is the radical form of x - 9/8

Answers

Answer:

Step-by-step explanation:

Please use " ^ " to indicate exponentiation.

Your "x - 9/8" should be     x ^(-9/8).

The 8 represents "the eighth root" of x, and the -9 represents the power to which x is to be raised.  Finally, the " - " sign shows that this 9th power is in the denominator.

x ^(-9/8)     in radical form is     ----------------

[tex]1 divided by \sqrt[8]{x^9\\} \\[/tex]

A radioactive substance decays exponentially. A scientist begins with 350 milligrams of a radioactive substance. After 14 hours, 175 mg of the substance remains. How many milligrams will remain after 20 hours

Answers

Answer:

N(t)=N∗.5t/h where n(t) is amount of substance left, N = initial amount, t = current time, and h = half-life time.h = 24 hours t= 45 hours, N = 130mg

therefore, N(t)=130∗.545/24=35.44mg

Step-by-step explanation:

N(t)=N∗.5t/h where n(t) is amount of substance left, N = initial amount, t = current time, and h = half-life time.h = 24 hours t= 45 hours, N = 130mg

therefore, N(t)=130∗.545/24=35.44mg

Answer:

≈ 130 mg

Step-by-step explanation:

This is about the half-life of the substance.

There is a formula for this kind of calculations:

N(t)= N₀*(0.5)^(t/T), where

N(t) = substance left after time period of t,t = time passed,N₀ = initial amount of the substance,T = hal-life time of the given substance.

In our case, we have:

N₀ = 350 mg,t= 20 hours,T = 14 hours  as half of substance decays during this time period,

And the calculation:

N(20)= 350*(0.5)^(20/14)N(20) ≈ 130 mg

Answer: about 130 mg of substance remains after 20 hours

You need to prepare 30mL solution of a 1:8 syrup solution. You have on hand 50% syrup solution and a 1:20 soda solution. How many mL of each solution do you need to create the final solution?

Answers

Answer:

5 ml of 50% syrup solution will be used to create the final solution

Step by step Explanation:

Let the amount of 50% solution that was used = b

Which means ( 30 - b ) is the amount of 1/200 solution used then we can derive an equation as follows,

set up will then be,

0.5b +0.05(30 -b) = 1/8 (30)

We can simplifiy this as

0.5b+ 1.5 -0.05b = 3.75

Then make b the subject of the formula we have

0.45b = 2.25

b= 2.25/0.45

b = 5 ml

Therefore, 5ml of 50% syrup solution will be used to create the final solution

if a man works 400km in 6 minutes.How long will he work in 9 minutes​

Answers

Answer:

600 km

Step-by-step explanation:

400 km  =       x    

  6 min         9 min  

cross multiply:

6x = 400 ( 9)

x = 3600 / 6

x = 600 km

Please answer this question now

Answers

Answer:

PQ = 17

Step-by-step explanation:

Tangents drawn to a circle from an external point are congruent, thus

TS = TU = 6

VU = VO = 20

PO = PQ = 37 - VO = 37 - 20 = 17

That is PQ = 17

un automóvil recorre 90 km con 2 galones de gasolina cuantos kilómetros recorre con 11 galones de gasolina y cuantos galones de gasolina necesita para recorrer 650 km

Answers

Answer:

Recorrera 495 km con 11 galones de gasolina

Y necesitara 14.44 galones para recorrer 650 km

Step-by-step explanation:

k          g                                                                  k             g

90         2                                                                 90           2

x            11                                                                650         x

=(11 x 90)/2                                                              =(650x2)/90

=990/2                                                                    =1300/90

=495 km                                                                 =14.44

Manipulate the radius and height of the cone, setting different values for each. Record the radius, height, and exact volume of the cone (in terms of π). The first one has been done for you. Also calculate the decimal value of the volume, and verify that it matches the volume displayed by the tool. (You might see some discrepancies in the tool due to rounding of decimals.)

Answers

Answer:

The decimal value of the volume already given= 1885.2 unit³

For radius 11 unit height 12 unit

Volume= 484π unit³

Volume= 1520.73 unit ³

For radius 4 unit height 6 unit

Volume= 32π unit³

Volume= 100.544 unit³

For radius 20 unit height 15 unit

Volume= 2000π unit³

Volume= 6284 unit³

Step-by-step explanation:

The decimal value of the volume already given= 600π

The decimal value of the volume already given= 600*3.142

The decimal value of the volume already given= 1885.2 unit³

For radius 11 unit height 12 unit

Volume= πr²h/3

Volume= 11²*12/3 *π

Volume= 484π unit³

Volume= 1520.73 unit ³

For radius 4 unit height 6 unit

Volume = πr²h/3

Volume= 4²*6/3(π)

Volume= 32π unit³

Volume= 100.544 unit³

For radius 20 unit height 15 unit

Volume= πr²h/3

Volume= 20²*15/3(π)

Volume= 2000π unit³

Volume= 6284 unit³

Here's the right answer.

figure a is a scale image of figure b. what is the value of x? please answer asap!

Answers

Greetings from Brasil...

According to the statement, one figure is scaled in relation to another, so we can apply similarity to polygons.....

So

BIG/small = BIG/small

or

small/BIG = small/BIG

12.5/10 = X/16

OR

10/12.5 = 16/X

12.5/10 = X/16

10X = 12.5 · 16

X = 200/10

X = 20

a symbol used to name one or more parts of a whole or asset or a location on the number line is a

Answers

Answer:

Fraction is the answer

50 points! I would appreciate an explanation, I actually want to know how to do this. Thanks! :P

Answers

Answer:

1.

(a) The Domain is the set of inputs of the function.

Considering that the function takes a period of 3 weeks (21 days), the domain is [0, 21], once we can't evaluate what happens after the 21st day.

[tex]\text{Domain is } [0, 21][/tex]

Otherwise, it could be [tex][0, \infty)[/tex]

Note: We include 0 and 21.

Once the greatest balance was $400, it will not exceed $400, either it doesn't show negative values.

[tex]\text{Range is } [0, 400][/tex]    

Note: We include 0 and 400.

(b)

Once the greatest balance was $400, when x=0, it seems that the y-value is half of $400, therefore, approximately $200. It also represents the initial value, the amount of money when she opened the account.

(c)

[tex]f(x)=B(d)[/tex]

[tex]B(12)=0[/tex]

(d)

It is in segment 4.

The balance equal to zero means that the y-value of the graph is zero, therefore in the x-axis.

Lilianna uses \dfrac{3}{4} 4 3 ​ start fraction, 3, divided by, 4, end fraction calories per minute just by sitting. She uses 111 more calorie per minute by walking. Lilianna uses a total of 12\dfrac{1}{4}12 4 1 ​ 12, start fraction, 1, divided by, 4, end fraction calories walking to the park. Lilianna uses the equation, d\left(\dfrac{3}{4}+1\right)=12\dfrac{1}{4}d( 4 3 ​ +1)=12 4 1 ​ d, left parenthesis, start fraction, 3, divided by, 4, end fraction, plus, 1, right parenthesis, equals, 12, start fraction, 1, divided by, 4, end fraction to represent the situation. What does the variable ddd represent in the equation? Choose 1 answer: Choose 1 answer: (Choice A) A Calories per minute Lilianna uses walking (Choice B) B Number of calories Lilianna would have used sitting (Choice C) C Number of minutes Lilianna walked

Answers

The Variable d in the equation represents the time per minute Lilianna spends walking to the park

Variable

Calories used by sitting = 3/4Calories used by walking = 1Total calories used walking to the park = 12 1/4

The equation:

d(3/4 + 1) = 12 1/4

d(3+4/4) = 12 1/4

d(7/4) = 49/4

d = 49/4 ÷ 7/4

= 49/4 × 4/7

= 49/7

d = 7

Complete question:

Lilianna uses 3/4 calories per minute just by sitting. She uses 1 more calorie per minute by walking. Liliana uses a total of 12 1/4 calories walking to the park. Lilianna uses the equation, d(3/4+1)=12 1/4 to represent the situation. What does the variable d represent in the equation?

Learn more about variable:

https://brainly.com/question/11885867

#SPJ1

maggie’s brother is 3 years younger than twice her age. The sum of their age is 24. How old is Maggie

Answers

Answer:

I HOPE IT WILL WORK

Step-by-step explanation:

let age of Maggie =x years

as given that Maggie brother is 3 year less than twice of her age

hence

brother = (2x-3) years

also given that sum of ages =24

hence

x+(2x-3)=24

3 x-3=24

3 x=27

x=9 years Maggie

so his brother=9-3=6 years

pls hit the star and brainlist it if you found it helpfull thanks

Given \qquad m \angle LONm∠LONm, angle, L, O, N is a straight angle. \qquad m \angle MON = 8x - 13^\circm∠MON=8x−13 ∘ m, angle, M, O, N, equals, 8, x, minus, 13, degrees \qquad m \angle LOM = 7x - 17^\circm∠LOM=7x−17 ∘ m, angle, L, O, M, equals, 7, x, minus, 17, degrees Find m\angle MONm∠MONm, angle, M, O, N:

Answers

Answer:

[tex] \boxed{99°}[/tex]

Step-by-step explanation:

m<MON = 8x - 13°

m<LOM = 7x - 17°

To find : m <MON

First, we have to find the value of x :

Create an equation

[tex] \mathrm{8x - 13 + 7x - 17 = 180}[/tex] ( sum of angle in straight line )

Collect like terms

[tex] \mathrm{15x - 13 - 17 = 180}[/tex]

Calculate

[tex] \mathrm{15x - 30 = 180}[/tex]

Move constant to R.H.S and change its sign

[tex] \mathrm{15x = 180 + 30}[/tex]

Calculate the sum

[tex] \mathrm{15x = 210}[/tex]

Divide both sides of the equation by 15

[tex] \mathrm{ \frac{15x}{15} = \frac{210}{15} }[/tex]

Calculate

[tex] \mathrm{x = 14}[/tex]

Now, let's find the value of m<MON

[tex] \mathrm{8x - 13}[/tex]

Plug the value of x

[tex] \mathrm{ = 8 \times 14 - 13}[/tex]

Calculate the product

[tex] \mathrm{ = 112 - 13}[/tex]

Calculate the difference

[tex] \mathrm{ = 99}[/tex] °

Hope I helped!

Best regards!

Answer:

48

Step-by-step explanation:

because i say so

Ahmad the trainer has two solo workout plans that he offers his clients: Plan A and Plan B. Each client does either one or the other (not both). On Monday there were clients 3 who did Plan A and 2 who did Plan B. On Tuesday there were 5 clients who did Plan A and 6 who did Plan B. Ahmad trained his Monday clients for a total of 3 hours and his Tuesday clients for a total of 7 hours. How long does each of the workout plans last? please help

Answers

Answer:

Plan A last for 30 minutes

Plan B last for 45 minutes

Step-by-step explanation:

There are two plans:

Plan A

Plan B

Monday

Plan A=3 clients

Plan B=2 clients

Total hours=3

Tuesday

Plan A=5 clients

Plan B=6 clients

Total hours=7

The equation for the unknown

3A + 2B=3 (1)

5A + 6B=7 (2)

Multiply (1) by 3 and (2) by (1)

9A + 6B=9 (3)

5A + 6B=7 (4)

Subtract (4) from (3)

4A=2

Divide both sides by 4

4A/4 = 2/4

A=1/2 hours

Substitute A=1/2 into (1)

3A + 2B=3

3(1/2) +2B=3

3/2 + 2B=3

2B= 3 - 3/2

2B= 6-3/2

2B=3/2

Divide both sides by 2

B=3/2÷2

=3/2×1/2

B=3/4 hours

A=1/2 hours

B=3/4 hours

60 minutes=1 hour

A=1/2 hours

1/2 × 60 minutes

=60/2

=30 minutes

B=3/4 hours

=3/4×60 minutes

=180/4

=45 minutes

Plan A last for 30 minutes

Plan B last for 45 minutes

find the missing part of the proportion 12/x = 3/7 x= _

Answers

Answer:

x = 28

Step-by-step explanation:

12/x = 3/7

Using cross products

3x = 12*7

3x = 84

Divide by 3

x = 28

Which of the following expressions demonstrates the distributive property?
3 + 4 + 5 = 4 + 3 + 5
-2(5 + 7) = -2(7 + 5)
O 3(-8 + 1) = 3(-8) + 3(1)
6[(7)(-2)] = [(6)(7)](-2)

Answers

Answer:

3(-8 + 1) = 3(-8) + 3(1)

Step-by-step explanation:

The distributive property is quite literally when you distribute numbers. This is the only instance of that happening here

The first two are the communitive property of addition, and the last one is the communitive property of multiplication.

Cheers.

Answer:

c

Step-by-step explanation:

Line R: 2x + 2y = 18 Line M: x + y = 9 Which statement is true about the solution to the set of equations?

Answers

Answer:

Step-by-step explanation:

2x + 2y = 18

-2x -2y = -18

0 = 0

infinite solution of equations

-5/6 + 1 2/9
Can some one help me out?

Answers

Answer:

[tex]2 \frac{4}{9} [/tex]

[tex] = \frac{ - 5}{6} + 1 \frac{2}{9} [/tex]

[tex] = \frac{ - 5}{6} + \frac{11}{9} [/tex]

[tex] = \frac{ - 5 \times 2 + 11 \times 1}{9} [/tex]

[tex] = \frac{ - 10 + 9}{9} [/tex]

[tex] = \frac{-1}{9} [/tex]

How do I solve this?​

Answers

Answer:

[tex]\Large \boxed{- \frac{1}{5}}[/tex]

Step-by-step explanation:

[tex]\displaystyle \sqrt[3]{-\frac{1}{125} }[/tex]

Distribute the cube root to the numerator and denominator.

[tex]\displaystyle -\frac{\sqrt[3]{1} }{\sqrt[3]{125} }[/tex]

Solve for the cube root.

[tex]\displaystyle - \frac{1}{5}[/tex]

ASAP PLEASE GIVE CORRECT ANSWER
In a rectangular coordinate system, what is the number of units in the distance from the origin to the point $(-15, 8)$? Enter your answer

Answers

distance of a point [tex](x,y)[/tex] from origin is $\sqrt{x^2+y^2}$

so distance is $\sqrt{(-15)^2+(8)^2}=\sqrt{225+64}=\sqrt{289}=17$

Answer:

Distance=17 units

Step-by-step explanation:

Coordinates of the origin: (0, 0)

Coordinates of the point in question: (-15, 8)

Distance formula for any two points [tex](x_1,y_1), (x_2,y_2)[/tex] on the plane:

[tex]distance=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2} \\distance=\sqrt{(-15-0)^2+(8-0)^2}\\distance=\sqrt{(15)^2+(8)^2}\\distance=\sqrt{225+64} \\distance=\sqrt{289} \\distance=17[/tex]

Duane is making a casserole for dinner. He has been cooking the casserole for 48 minutes. The casserole
needs to cook for 47 more minutes.
How many minutes does the casserole cook in total?

Answers

Answer:

95 minutes

Step-by-step explanation:

Add together how long it has been cooking plus how long it needs to cook

48+47 = 95

95 minutes

Answer:

155

Step-by-step explanation:

Add 60 and 48 to get 108 then add 108 and 47 to get 155

∠4 and ∠6 can be classified as:

Answers

Answer:

same side interior angles

Step-by-step explanation:

<4 and <6 are same side interior angles

Same  side interior angles are on the same side of the transversal and inbetween the two lines

Which point would be a solution to the system of linear inequalities shown below? {see image for inequalities}

(-10, -2)
(−5,2)
(10,7)
(10,−2)

Answers

Answer:

(10, -2)

Step-by-step explanation:

The inequalities are:

y < x - 7               (1)

y < (1/5)x - 2        (2)

To solve this problem, we have to solve both equations simultaneously and then find the value of x and y that makes the inequality true.

To solve the inequality, subtract inequality (2) from inequality (1) which gives:

0 < (4/5) x - 5

-(4/5)x < -5

Dividing both sides of the equation by -4/5 gives:

-(4/5)x / (-4/5) < -5/ (-4/5)

x > 6.25

Put x > 6.2 in inequality 1

y < 6.25 - 7

y < -0.75

The solution of the inequality is x > 6.25 and y < -0.75

From the list of option, the correct answer is (10, -2) since 10 > 6.25 and -2 < -0.75

Evaluate each expression. Name the property used in each step.

Answers

Answer:

7). 1

8). 3

9). 1

Step-by-step explanation:

7). [tex][3\div (2\times 1)]\frac{2}{3}[/tex]

  [tex]=[3\div 2]\frac{2}{3}[/tex]

  [tex]=\frac{3}{2}\times \frac{2}{3}[/tex]

  [tex]=1[/tex]

8). [tex]2(3\times 2-5)+3\times \frac{1}{3}[/tex]

  [tex]=2(6-5)+\frac{3}{3}[/tex]

  [tex]=2(6-5)+1[/tex]

  [tex]=2+1[/tex]

  = 3

9). [tex]6\times \frac{1}{6}+5(12\div 4-3)[/tex]

  [tex]=6\times \frac{1}{6}+5(\frac{12}{4}-3 )[/tex]

  [tex]=1+5(3-3)[/tex]

  = 1

help with math again please

Answers

ANSWER:

               It is C

NO EXPLANATION

Mildred’s salary has increased from £24,600 to £25,338. By what percentage has her salary increase?

Answers

Answer:

The answer is 3%

Step-by-step explanation:

To find the percentage increase we use the formula

[tex]Percentage \: change = \frac{ change}{original \: quantity} \times 100[/tex]

To find the change subtract the smaller quantity from the bigger one

From the question

original price = $24,600

Current price = $ 25,338

Change = $25,338 - $ 24,600

Change = $ 738

So the percentage increase is

[tex] \frac{738}{24600} \times 100[/tex]

[tex] = \frac{3}{100} \times 100[/tex]

We have the final answer as

Percentage increase = 3%

Hope this helps you

Other Questions
For the following transaction, answer the questions that follow in accordance with the rules of journalizing and the double-entry accounting system: Transaction: Drawing by owner amounted to $1,500.Required:a. Which two accounts are affected ? b. What kind of accounts are they? c. Do the account balances increase or decrease? d. Do we debit or credit the accounts? Production possibilities frontiers are usually bowed outward. This is because a. resources are specialized; that is, some are better at producing particular goods rather than other goods. b. of the effects of technological change. c. the opportunity cost of producing a good decreases as more and more of that good is produced. d. the more resources a society uses to produce one good, the fewer resources it has available to produce another good. HELPPPPP ASAPPPPSelect the correct answer.A volleyball player sets a volleyball straight up into the air. The height of the volleyball, h(t), is modeled by this equation, where e represents thetime, in seconds, after that ball was set.= -16t2 + 20t + 6The volleyball reaches its maximum height after 0.625 seconds. What is the maximum height of the volleyballA. 11.625 feetB. 12.25 feetC. 8.5 feetD. 1.625 feet Simplify (3n - 2m)^2 = Can someone break this down for me? I don't understand why I'm having issues with this. Consider two projects. The first project pays benefits of $85 today and nothing else. The second project pays nothing today, nothing one year from now, but $104 two years from now. a. Which project would be preferred if the discount rate were 0%? b. What if the rate increased to 10%? c. Find the Internal Rate of Return. need help asap please help let quick eeeeeeeeeeeeeeee two similar cups are 3 cm and 5 cm deep if the larger cups hold 675 cm cube of water what is the volume of the smaller one Key facts and assumptions concerning Kroger Company, at December 12, 2007, appear below. Using this information, answer the questions following. Facts and Assumptions Yield to maturity on long-term government bonds 4.54% Yield to maturity on company long-term bonds 6.32% Coupon rate on company long-term bonds 7.50% Market price of risk, or risk premium 6.30% Estimated company equity beta 1.05 Stock price per share $ 25.97 Number of shares outstanding 681.2 million Book value of equity $ 4,965 million Book value of interest-bearing debt $ 6,674 million Tax rate 35.0% a. Estimate Kroger's cost of equity capital. b. Estimate Kroger's weighted-average cost of capital. Prepare a spreadsheet or table showing the relevant variables. What chemical bonds hold atoms? On November 1, Alan Company signed a 120-day, 8% note payable, with a face value of $9,000. What is the maturity value (principal plus interest) of the note on March 1 round 38562 to one significant figure Which number is closest to O on the number line?-0.260.30.275-0.51 The areas of two similar octagons are 4 m and 9 m. What is the scale factor of their side lengths? PLZ PLZ HELP PLZ -3x+2y=6 Find the intercepts. Show your work. Can you help Jorge organize the results into a two-way frequency table? 1. Which is an example of a natural right?(1) freedom of speech(2) a public trial(3) a license to practice medicine(4) paying taxes(5) government payments to the unemployed Assume the following: (1) the interest rate on 6-month treasury bills is 8 percent per annum in the United Kingdom and 4 percent per annum in the United States; (2) today's spot price of the pound is $1.50 while the 6-month forward price of the pound is $1.485.If the price of the 6-month forward pound were to ____, U.S. investors would no longer earn an extra return by shifting funds to the United Kingdom.a. Rise to $1.52b. Rise to $1.53c. Fall to $1.48d. Fall to $1.47 Match each quadratic equation with its solution set. The size of a television screen is given as 95 cm, correct to the nearest 5 cm.Write down the upper bound of the size of the television screen. IblMessage.txt=welcome to fiji.what is the error in the coding and what type of error is it?(explain)