A system of equations consists of the two equations shown.
{4x+5y=18
6x−5y=20
Which procedure will produce a single equation in one variable? Select all the procedures that apply.
A. Subtract the first equation from the second equation.
B. Subtract the second equation from the first equation.
C. Multiply the first equation by 18; multiply the second equation by 18; add the equations.
D. Multiply the first equation by − 6; multiply the second equation by 4; add the two equations.
E. Multiply the first equation by 3; multiply the second equation by − 2; add the two equations.
F. Multiply the first equation by 3; multiply the second equation by 2; subtract the equations in any order.

Answer:

15.7% of students made above an 89.

Step-by-step explanation:

If the data is normally distributed, the standard deviation is 7, and the mean is 82, then about 68.2% of students made between 75 and 89. 13.6% made between 90 and 96, and 2.1% made over 96. 13.6+2.1=15.7%

Answer:

The dimensions or Area of the rectangle is 1200cm².

Answer:

Explained below.

Step-by-step explanation:

Enter the data in an Excel sheet.

(a)

Go to Insert → Chart → Scatter.

Select the first type of Scatter chart.

The scatter plot is attached below.

(b)

The scatter plot with the line of best fit is attached below.

The line of best fit is:

[tex]y=-0.8046x+103.56[/tex]

(c)

Compute the value of x for y = 30 as follows:

[tex]y=-0.8046x+103.56[/tex]

[tex]30=-0.8046x+103.56\\\\0.8046x=103.56-30\\\\x=\frac{73.56}{0.8046}\\\\x\approx 91.42[/tex]

Thus, the Advance Mathematics mark of a student who scores 30 out of 100 in English is 91.42.

(d)

The Pearson's Correlation Coefficient is:

[tex]r=\frac{n\cdot \sum XY-\sum X\cdot \sum Y}{\sqrt{[n\cdot \sum X^{2}-(\sum X)^{2}][n\cdot \sum Y^{2}-(\sum Y)^{2}]}}[/tex]

  [tex]=\frac{14\cdot 44010-835\cdot 778}{\sqrt{[14\cdot52775-(825)^{2}][14\cdot 47094-(778)^{2}]}}\\\\= -0.7062\\\\\approx -0.71[/tex]

Thus, the Pearson's Correlation Coefficient is -0.71.

(e)

A correlation coefficient between ± 0.50 and ±1.00 is considered as a strong correlation.

The correlation between Advanced Mathematics and English results is -0.71.

This implies that there is a strong negative correlation.

Answer:

t= 0.4933

t ≥ t ( 0.025 ,8 ) = 2.306

Since the calculated value of t= 0.4933 is less than t ( 0.025 ,8 ) = 2.306 therefore we accept the null hypothesis at 5 % significance level . On the basis of this we conclude that the book had no effect on their scores.

Step-by-step explanation:

We state our null and alternative hypotheses as

H0: ud= 0 Ha: ud≠0

The significance level is set at ∝= 0.05

The test statistic under H0 is

t= d`/ sd/√n

which has t distribution with n-1 degrees of freedom

The critical region is t ≥ t ( 0.025 ,8 ) = 2.306

Computations

Student       Scores before      Scores after    Difference           d²

                        reading book                    ( after minus before)

1                          720                   740             20                       400

2                        860                   860              0                           0

3                        850                   840             -10                       100

4                        880                   920             40                       1600

5                        860                   890             30                        900

6                        710                    720              10                         100

7                       850                    840              -10                       100

8                      1200                  1240             40                        1600

9                      950                    970              20                           40

∑                    6930                  8020           140                         4840

d`= ∑d/n= 140/9= 15.566

sd²= 1/8( 4840- 140²/9) = 1/8 (4840 - 2177.778) = 2662.22/8= 332.775

sd= 18.2422

t= 3/ 18.2422/ √9

t= 0.4933

Since the calculated value of t= 0.4933 is less than t ( 0.025 ,8 ) = 2.306 therefore we accept the null hypothesis at 5 % significance level . On the basis of this we conclude that the book had no effect on their scores.

Answer:

  log(1/10) = -1

Step-by-step explanation:

Use the law of exponents and the meaning of logarithm.

  1/10 = 10^-1

  log(10^x) = x

So, you have ...

  log(1/10) = log(10^-1)

  log(1/10) = -1

Answer:

The probability that the amount of gas in Sarah's car is exactly 7 gallons is 0.067.

Step-by-step explanation:

Let the random variable X represent the amount of gas in Sarah's car.

It is provided that [tex]X\sim Unif(1, 16)[/tex].

The amount of gas in a car is a continuous variable.

So, the random variable X follows a continuous uniform distribution.

Then the probability density function of X is:

[tex]f_{X}(x)=\frac{1}{b-a};\ a<X<b[/tex]

For a continuous probability distribution the probability at an exact point is 0.

So, to compute the probability that the amount of gas in Sarah's car is exactly 7 gallons use continuity correction on both sides:

P (X = 7) = P (7 - 0.5 < X < 7 + 0.5)

              = P (6.5 < X < 7.5)

              [tex]=\int\limits^{7.5}_{6.5} {\frac{1}{16-1}} \, dx \\\\=\frac{1}{15}\times |x|^{7.5}_{6.5}\\\\=\frac{1}{15}\times (7.5-6.5)\\\\=\frac{1}{15}\\\\=0.0666667\\\\\approx 0.067[/tex]

Thus, the probability that the amount of gas in Sarah's car is exactly 7 gallons is 0.067.

Answer:

its multiple choice

A. 26inches (1inch/25.4mm)

B. 26inches (25.4mm/1inch)

C. 25.4inches (1mm/26inch)

D. 26inches (1mm/25.4inch)

and its b

Answer:

2.8

Step-by-step explanation:

11.1-8.3=2.8

HOPE I HELPED

PLS MARK BRAINLIEST

DESPERATELY TRYING TO LEVEL UP

✌ -ZYLYNN JADE ARDENNE

JUST A RANDOM GIRL WANTING TO HELP PEOPLE!

                            PEACE!

Answer:

(1) Therefore, a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it is [0.4348, 0.5252].

(2) We can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval

(3) A survey should include at least 3002 people if we wanted the margin of error for the 90% confidence level to be about 1.5%.

Step-by-step explanation:

We are given that a simple random sample of 331 American adults who do not have a four-year college degree and are not currently enrolled in school, 48% said they decided not to go to college because they could not afford school.

Firstly, the pivotal quantity for finding the confidence interval for the population proportion is given by;

                         P.Q.  =  [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex]  ~ N(0,1)

where, [tex]\hat p[/tex] = sample proportion of Americans who decide to not go to college = 48%

           n = sample of American adults = 331

           p = population proportion of Americans who decide to not go to

                 college because they cannot afford it

Here for constructing a 90% confidence interval we have used a One-sample z-test for proportions.

So, 90% confidence interval for the population proportion, p is ;

P(-1.645 < N(0,1) < 1.645) = 0.90  {As the critical value of z at 5% level

                                                        of significance are -1.645 & 1.645}  

P(-1.645 < [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < 1.645) = 0.90

P( [tex]-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < [tex]\hat p-p[/tex] < [tex]1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.90

P( [tex]\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < p < [tex]\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.90

90% confidence interval for p = [ [tex]\hat p-1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] , [tex]\hat p+1.645 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ]

 = [ [tex]0.48 -1.96 \times {\sqrt{\frac{0.48(1-0.48)}{331} } }[/tex] , [tex]0.48 +1.96 \times {\sqrt{\frac{0.48(1-0.48)}{331} } }[/tex] ]

 = [0.4348, 0.5252]

(1) Therefore, a 90% confidence interval for the proportion of Americans who decide to not go to college because they cannot afford it is [0.4348, 0.5252].

(2) The interpretation of the above confidence interval is that we can be 90% confident that the proportion of Americans who choose not to go to college because they cannot afford it is contained within our confidence interval.

3) Now, it is given that we wanted the margin of error for the 90% confidence level to be about 1.5%.

So, the margin of error =  [tex]Z_(_\frac{\alpha}{2}_) \times \sqrt{\frac{\hat p(1-\hat p)}{n} }[/tex]

              [tex]0.015 = 1.645 \times \sqrt{\frac{0.48(1-0.48)}{n} }[/tex]

              [tex]\sqrt{n} = \frac{1.645 \times \sqrt{0.48 \times 0.52} }{0.015}[/tex]

              [tex]\sqrt{n}[/tex] = 54.79

               n = [tex]54.79^{2}[/tex]

               n = 3001.88 ≈ 3002

Hence, a survey should include at least 3002 people if we wanted the margin of error for the 90% confidence level to be about 1.5%.

Answer:

27.73 feet

Step-by-step explanation:

Use the Pythagorean theorem. It easiest to think of the distance between the two friends as a triangle in the rectangle. One side is 12ft and the other is 25ft.

12^2+25ft^2=769

The square root of 769 is 27.73

Answer:

27.73 Ft

Step-by-step explanation:I took the test

Answer:

1 +3i

Step-by-step explanation:

(4 - 2i) - (3 - 5i)

Subtract the reals

4 - 3 =1

Subtract the imaginary

-2i - -5i

-2i + 5i = 3i

1 +3i

Answer:

A

Step-by-step explanation:

Subtract all real numbers

4 - 3 = 1

Subtract all imaginary numbers

-2i - (-5i) = 3i

Put back together

1 + 3i

Best of Luck!

Answer:

A) ( -8, -32 )

Step-by-step explanation:

Given function : f (x,y) = 21 - 4x^2 - 16y^2

point p( 1,1,1 ) on surface

Gradient of F

attached below is the detailed solution

Answer:

Step-by-step explanation:

● h(x) = 2-2x

The domain is {-3,-2,1,5}

● h(-3) = 2-2×(-3) = 2+6 = 8

● h(-2) = 2 -2×(-2) = 2+4 = 6

● h(1) = 2-2×1 = 2-2 = 0

● h(5) = 2-2×5 = 2-10 = -8

The range is {-8,0,6,8}

x = liters of 1% solution

y = liters of 5% solution

x + y = 16

0.01x + 0.05y = 0.04*16 = 0.64

y = 16 - x

0.01x + 0.05(16 - x) = 0.64

0.01x + 0.8 - 0.05x = 0.64

0.16 = 0.04x

x = 4

y = 12

Answer:

A, E

Step-by-step explanation:

There should be 2^8-1 proper subsets of A. Its every one besides { }

Answer:

Step-by-step explanation:

f(x) = (x+1)³ + 4

To find f-¹(x) equate f(x) to y

That's

y = (x+1)³ + 4

Next interchange the terms x becomes y and y becomes x

That's

x = ( y+1)³ + 4

Make y the subject

(y+1)³ = x - 4

Find the cube root of both sides

That's

[tex]y + 1 = \sqrt[3]{x - 4} [/tex]

Send 1 to the right side of the equation

That's

[tex]y = \sqrt[3]{x - 4} - 1[/tex]

So we have the final answer as

[tex]f ^{ - 1} (x) = \sqrt[3]{x - 4} - 1[/tex]

Hope this helps you

Answer:

option 1

Step-by-step explanation:

f(x)=(x+1)³+4

to find the inverse interchange the variable and solve for y

inverse f(x)=(y+1)³+4

x=(y+1)³+4

x-4=(y+1)³

y+1=∛x-4

y=∛x-4 -1

Answer:

252

Step-by-step explanation:

Divide 7812 by 31 and we get the average daily answer... Hope this helps!!

Answer:

[tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.

Step-by-step explanation:

Given that:

Side of an equilateral triangle = 8 cm

To find:

Area of the triangle will be:

[tex]A.\ 16\sqrt3\ cm^2[/tex]

[tex]B.\ \dfrac{32}{3} cm^2[/tex]

[tex]C.\ 48\ cm^2[/tex]

[tex]D.\ 36\sqrt3\ cm^2[/tex]

Solution:

First of all, let us have a look at the formula for area of an equilateral triangle:

[tex]A =\dfrac{\sqrt3}{4}a^2[/tex]

Where [tex]a[/tex] is the side of equilateral triangle and an equilateral triangle is a closed 3 sided structure in 2 dimensions which has all 3 sides equal to each other.

Here, we are given that side, [tex]a=8\ cm[/tex]

Putting the value in formula:

[tex]A =\dfrac{\sqrt3}{4}\times 8^2\\\Rightarrow A =\dfrac{\sqrt3}{4}\times 64\\\Rightarrow A =\sqrt3\times 16\\OR\\\Rightarrow \bold{A =16\sqrt3\ cm^2}[/tex]

Hence, [tex]A.\ 16\sqrt3\ cm^2[/tex] is the correct answer.

Answer:

a)

H₀ : µd = 0  

H₁ : µd < 0  

b)

The test statistic is

tₙ₋₁ = α / s√n

c)

at 0.10 level of significance,

tₙ₋₁ , ₐ

t₃₀₋₁ , ₀.₁₀ = t₂₉, ₀.₁₀ = 1.311

d)

given that  T(critical) = 1.62

∴ T(critical) = 1.62 > t₂₉, ₀.₁₀ = 1.311

at 10% level of significance,

REJECT H₀

Since 1.62 > 1.311, we can reject the null hypothesis.

Answer:

Attachment 1 : Option A,

Attachment 2 : Option C

Step-by-step explanation:

( 1 ) Here we know that " n " is 6. Now remember if n is odd, the number of petals on the graph will be n. However if n is even, the number of petals on the graph will be 2n.

6 is even, and hence the number of petals will be 2(6) = 12 petals. Solution : 12 petals

( 2 ) To solve such problems we tend to use the equation [tex]z = x + y * i = r(cos\theta +isin\theta)[/tex] where [tex]r = \sqrt{x^2+y^2}[/tex] etc. Here I find it simpler to see each option, and convert each into it's standard complex form. It might seem hard, but it is easy if you know the value of (cos(5π / 3)) etc...

The answer here will be option c, but let's prove it,

cos(5π / 3) = 1 / 2,

sin(5π / 3) = [tex]-\frac{\sqrt{3}}{2}[/tex]

Plugging those values in for " [tex]8\left(\cos \left(\frac{5\pi }{3}\right)+i\sin \left(\frac{5\pi }{3}\right)\right)[/tex] "

[tex]8\left(-\frac{\sqrt{3}i}{2}+\frac{1}{2}\right)[/tex]

= [tex]8\cdot \frac{1}{2}-8\cdot \frac{\sqrt{3}i}{2}[/tex] = [tex]4-4\sqrt{3}i[/tex]

Hence proved that your solution is option c.

Answer:

Which polynomial is prime?

7x2 – 35x + 2x – 10

9x3 + 11x2 + 3x – 33  

10x3 – 15x2 + 8x – 12  

12x4 + 42x2 + 4x2 + 14

Step-by-step explanation:

Which polynomial is prime?

7x2 – 35x + 2x – 10

9x3 + 11x2 + 3x – 33  

10x3 – 15x2 + 8x – 12  

12x4 + 42x2 + 4x2 + 14 SO IT IS RIGHT

Answer:

x = 6

Step-by-step explanation:

In the third line of the solution on right side of the equal sign, middle term should be 8x instead of 4x.

The final value of x will be 6.

[tex] PQ^2 + QO^2 = PO^2 \\

x^2 + 8^2 = (4+x)^2 \\

x^2 + 64 = 16 + 8x + x^2 \\

64 = 16 + 8x \\

64 - 16 = 8x \\

48 = 8x \\

6 = x\\[/tex]

Answer:

The author have to use his/her phone less than 20 hours in a month in order for Don’tTalkMuch's is a deal to be better than TalkLots's is.

Step-by-step explanation:

Call X is the number of hours that the author uses on monthly basis.

Total bill value if the author uses Don’tTalkMuch service is $80 + $1 X.

Total bill value if the author uses TalkLots service is $20 + $4X

The total fees between 2 providers equal as:

$80 + $1 X = $20 + $4X => 3X = $60 => X = 20

Hence: The author have to use his/her phone less than 20 hours in a month in order for Don’tTalkMuch's is a deal to be better than TalkLots's is.

Answer:

The present value is  [tex]PV = \$ 396,987[/tex]

Step-by-step explanation:

From the question we are told that

   The  interest payment per year is  [tex]C = \$ 85[/tex]

    The principal payment is  [tex]P = \$ 1000[/tex]

     The  duration is  n =  8   years

      The  interest rate is  [tex]r = 10\% = 0.10[/tex]

The present value is  mathematically represented as

      [tex]PV = [ \frac{C}{r} * [1 - \frac{1 }{ (1 +r)^n} ] + \frac{P}{(1 + r)^n} ][/tex]

substituting values

      [tex]PV = [ \frac{85}{0.10} * [1 - \frac{1 }{ (1 +0.10)^8} ] + \frac{1000}{(1 + 0.10)^ 8} ][/tex]

      [tex]PV = \$ 396,987[/tex]

Complete Question

A population has a mean mu μ equals = 77 and a standard deviation σ = 14. Find the mean and standard deviation of a sampling distribution of sample means with sample size n equals = 26

Answer:

The mean of sampling distribution of the sample mean ( [tex]\= x[/tex]) is [tex]\mu_{\= x } = 77[/tex]

The standard deviation of sampling distribution of the sample mean ( [tex]\= x[/tex]) is  

    [tex]\sigma _{\= x} = 2.746[/tex]

Step-by-step explanation:

From the question we are told that

    The population mean is  [tex]\mu = 77[/tex]

     The  standard deviation is  [tex]\sigma = 14[/tex]

     The sample size is  [tex]n = 26[/tex]

Generally the standard deviation of sampling distribution of the sample mean ( [tex]\= x[/tex]) is  mathematically represented as

           [tex]\sigma _{\= x} = \frac{ \sigma }{ \sqrt{n} }[/tex]

substituting values  

          [tex]\sigma _{\= x} = \frac{ 14}{ \sqrt{26} }[/tex]

          [tex]\sigma _{\= x} = 2.746[/tex]

Generally the mean of sampling distribution of the sample mean ( [tex]\= x[/tex]) is  equivalent to the population mean i.e  

      [tex]\mu_{\= x } = \mu[/tex]

      [tex]\mu_{\= x } = 77[/tex]

Answer:

=6 units squared

Step-by-step explanation:

area=1/2h(a+b)

        =1/2×2(4+2)

        =6

Answer:

45

Step-by-step explanation:

2 digit number starts from 10 ends at 99

between 10 and 19 there is only one number whose tens digit is more than ones digit.

that is 10

between 20 and 29 there are two numbers

20 and 21

like the same

between 30 and 39 there are 3 numbers

10–19. 1

20–29. 2

30–39. 3

40–49. 4

50–59. 5

60–69. 6

70–79. 7

80–89. 8

99–99. 9

sum of first n natural numbers is n(n+1)/2

9(9+1)/2=45

Three numbers between 10 and 99 have tens places that are precisely three times larger than their one's places.

The foundation of our whole number system is place value. In this approach, the value of a digit in a number is determined by where it appears in the number.

The tens digit must be three times larger than the units digit in order to meet the requirement. The units digit can have one of the following values: 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9.

Since we are seeking two-digit integers, it is not possible if the unit digit is zero for the tens digit also be zero.

In the case when the unit digit is 1, the tens digit must be 3, resulting in the number 31. Similar to the previous example, if the unit digit is 2, the tens digit must be 6, resulting in the number 62.

As we proceed, we discover the following integers meet the condition:

31, 62, 93

Therefore, there are three numbers from 10 to 99 that have a tens place exactly 3 times greater than their one's place.

Learn more about place values here:

https://brainly.com/question/27734142

#SPJ3

Answer:

D. neither.

Step-by-step explanation:

A function is when one x-value only has one corrisponding y-value.

The answer it's D. Neither

Step-by-step explanation:

Ellen - 115/23

Classmates and Ellen got = 5 each