Need help !!!What is the first step to solve the following system of equations using substitution?

Answer:

Step-by-step explanation:

To solve this, we are going to make an age table:

                       Age Now                 Age 10 years ago

Tanya

Elliot

Filling the in the Age Now column comes from the first sentence. If Elliot is 2 times Tanya's age and we don't know Tanya's age, then Tanya's age is x and Elliot's age is 2x:

            Age Now                Age 10 years ago

Tanya         x

Elliot         2x

Filling in the Age 10 years ago column simply requires that we take their ages in the Age Now column and subtract 10 from each age:

         Age Now                Age 10 years ago

Tanya     x                              x - 10

Elliot      2x                           2x - 10

Since the question is How old is Elliot now based on the fact that 10 years ago....blah, blah, blah, we are using the ages in the 10 years ago column to write our equation. It says:

10 years ago, Elliot was 4 times as old as Tanya. Translated into mathspeak:

2x - 10 = 4(x - 10) and

2x - 10 = 4x - 40 and

-2x = -30 so

x = 15. That means that Elliot is 30 and Tanya is 15

Step-by-step explanation:

it is simple.

there is a constant speaking time of 25 minutes.

the duration of the meeting is the speaking time plus the question answering time.

so,

q = 1 means t = 25 + 1 = 26

q = 2 means t = 25 + 2 = 27

q = 3 means t = 25 + 3 = 28

q = 8 means t = 25 + 8 = 33

Answer:

-11, 3

Step-by-step explanation:

We know one of the roots are

[tex](x+ 4) {}^{2} = 49[/tex]

[tex]x + 4 = - 7[/tex]

[tex]x + 4 = 7[/tex]

[tex]x = - 11[/tex]

or

[tex]x = 3[/tex]

from 0 to 20

neither the seconds nor the height are likely to be negative.

Answer:

Step-by-step explanation:

You need to find the model for this situation using the points given. If you are given 13 mg immediately, the coordinate point for that is (0, 13), where the x coordinate is the time in minutes and the y coordinate is the amount of dye in mg.

If after 12 minutes, 4.75 mg remain, the coordinate point for that is (12, 4.75). Just so you know, the time unit always goes in for x, never for y.

Now that we have these coordinates we are going to use them as a system and find the model. Begin with the point (0, 13) in

[tex]A=a(b)^t[/tex] where A is the amount left in the body, a is the initial amount injected, b is the rate at which it decays, and t is the time in minutes. Plug in the first set of coordinates:

[tex]13=a(b)^0[/tex] and since anything raised to the power of 0 is equal to 1, we have

13 = a. Now we can use that and write another equation with the other set of coordinates to solve for b:

[tex]4.75=13(b)^{12}[/tex] and divide both sides by 13 (don't round anything yet) to get

.3653846154 = b¹². Now take the 12th root of both sides (you need a scientific calculator for this) to get that

b = .9195228407  Yikes.

Now for the model, using the fact that a = 13 and b = .9195228407:

[tex]A=13(.9195228407)^t[/tex]  

We are told that the amount that we are allowed to leave with still remaining in our system cannot be more than 2 mg, so we sub in a 2 for A:

[tex]2=13(.9195228407)^t[/tex] and begin by dividing away 13 to get

[tex].1538461538=.9195228407^t[/tex]  Take the natural log of both sides, which allows us to bring the t out front:

ln(.1538461538) = t ln(.9195228407) and finally divide by ln(.9195228407) to get

t = 22.3 minutes

The probability notation for the probability for choosing a green marble is [tex]P(G)=\frac{n(G)}{n(T)}[/tex], where [tex]n(G)[/tex] denotes the number of green marbles and [tex]n(T)[/tex] denotes the number of total marbles in the bag (or from wherever we are choosing).

The probability of occurrence of an event is the ratio of the number of favorable outcomes and the total number of outcomes, where the favorable outcomes are the outcomes that implies the occurrence of the event.

Here, the event is "choosing a green marble". So, the number of green marbles in the bag is the number of favorable outcomes and the total number of marbles in the bag is the total number of outcomes.

Denoting [tex]G[/tex] as the event of "choosing a green marble", the notation [tex]P(G)[/tex] denotes the probability of event [tex]G[/tex], that is, probability of choosing a green marble.

Denoting [tex]n(G)[/tex] and [tex]n(T)[/tex] as the number of green marbles and total number of marbles respectively, by the definition, the probability notation for the probability for choosing a green marble is given as [tex]P(G)=\frac{n(G)}{n(T)}[/tex].

Learn more about probability notation here:

https://brainly.com/question/22159331

Answer:

D

Step-by-step explanation:

[tex]8x \sqrt{2} - 4 \sqrt{2} [/tex]

Answer:

Probably the first three answers

Step-by-step explanation:

The rest are

4) 3×5=15 (which is not 8)

5) 6×2=12 (≠8)

So it's just the first three

Answer:

a = m/c

~~~~~~~~~~~~~~~~~~~~~~~

m=ca

divide both sides by c

you get a = m/c

Step-by-step explanation:

Answer:

a = m/c

Step-by-step explanation:

m = ca

divide both sides by c

m/c = ca/c

m/c = a

:.a = m/c

Answer:

x=5

Step-by-step explanation:

x=[tex]\sqrt{25}[/tex]

x=5

Answer:

2730÷30=91

Step-by-step explanation:

take the number of books and divide it by the number of books each shelve can hold and ull get ur answer

Answer:

28.

      megabyte- [tex]10^6[/tex]

      terabyte- [tex]10^{12}[/tex]

      gigabyte- [tex]10^9[/tex]

       For [tex]10^6, 10^9, 10^{12},[/tex] and [tex]10^{15}[/tex], put the 1, and add the exponent # of 0s.

29.

       The cube is 6×6×6   or    216 in. It would be 6³, because the 6 is multiplied 3 times.

30.

 a. 10

 b. 5120

I hope this helps!

pls ❤ and mark brainliest pls!

Answer:

Question 28

megabyte: 10⁶

terabyte: 10¹²

gigabyte: 10⁹

Question 29

6³

Question 30

a. 20

b. 5,120

Answer:

d isósceles hijo muy graciosa ya no me acuerdo de nada y tu q ases hablas con el

Let's solve

Using Pythagorean theorem

[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]

[tex]\\ \sf\longmapsto c^2=8^2+5^2[/tex]

[tex]\\ \sf\longmapsto c^2=64+25[/tex]

[tex]\\ \sf\longmapsto c^2=89[/tex]

[tex]\\ \sf\longmapsto c=\sqrt{89}[/tex]

[tex]\\ \sf\longmapsto c\approx 9.22[/tex]

Answer:

I think this is the right answer but last two signs are incorrect

Hope this will help

Answer:

i dont know

Step-by-step explanation:

Answer:

13

Step-by-step explanation:

(4+√3)(4-√3) = (4)^2-(√3)^2 =16-3 = 13

Answer:

Step-by-step explanation:

(a + b)(a -b) =a² - b²

a = 4 and  b = √3

(4 + √3)(4 - √3)= 4² - (√3)²

                        = 16 - √3*√3

                        = 16 - 3

                        =  13

Answer:

C.

–5; –135; –10,935

Step-by-step explanation:

Answer:

C. -5; -135, -10,935

Step-by-step explanation:

...............................................................................................................................................

Step-by-step explanation:

jsndmdmsmsnananansndbdbnd

Answer:

1287.48 km

Step-by-step explanation:

80 miles = 128.748 km

Putting in 'x' for distance

x = 80*10  

x = 800 miles

or

x = 1287.48 km

Answer:

Step-by-step explanation:

Answer:

The two bottom angles of this triangle are both represented by the same variable, in this case, an x. This means, that both of the bottom angles are equal to each other.

So we have:

32 + x + x = 180 (since the TOTAL angles of a triangle adds up to 180)

32 + 2x = 180 (combine the 2 x's together)

2x = 148 (subtract a 32 from both sides)

x = 74

Let me know if this helps!

Answer:

2x + 3

Step-by-step explanation:

(10x² + 19x + 6) ÷ (5x + 2)​ =

= (10x² + 15x + 4x + 6) ÷ (5x + 2)​

= [5x(2x + 3) + 2(2x + 3)] ÷ (5x + 2)​

= [(5x + 2)(2x + 3)] ÷ (5x + 2)​

= 2x + 3

Answer:

2x+3 is your answer

Answer:

Could you Write the question more clearly?

Step-by-step explanation:

Answer:

x=2

Step-by-step explanation:

We can use the Pythagorean theorem since this makes a right triangle

a^2+b^2 = c^2

The radius is 1.5

1.5^2 + x^2 = (1+1.5)^2

1.5^2 +x^2 = 2.5^2

2.25+x^2=6.25

Subtract 2.25 from each side

x^2 = 4

Taking the square root of each side

x= 2

Answer:A

Step-by-step explanation:Took quiz

9514 1404 393

Answer:

Step-by-step explanation:

The speed is the ratio of the change in distance to the corresponding change in time.

Vehicle A moves from a position of 12 m to one of 28 m in 50 seconds, so its speed is ...

  A = (28 -12)/50 m/s = 16/50 m/s = 0.32 m/s

Vehicle B moves from 0 to 28 m in 50 seconds, so its speed is ...

  B = (28 m)/(50 s) = 0.56 m/s

Answer:

[tex]→1 \frac{2}{3} + 2 \frac{3}{4} \\ = \frac{5}{3} + \frac{11}{4} \\ = \frac{20 + 33}{12} \\ = \frac{53}{12}\\ =\boxed{4\frac{5}{12}}✓[/tex]

Steps:

1 2/3 + 2 3/4 can also be written as...

5/3 + 11/4

The LCD is 12 so we make both fractions have a denominator of 12.

That gives us 20/12+33/12

Now you can add the numerators (but leave the denominator the same)

That gives us 53/12, but our simplified version would give us 4 5/12 as our final answer.

Answer:

[tex]4\frac{5}{12\\}[/tex]

Please mark brainliest if that helps!

Answer:

(1, -13)

Brainliest, please!

Step-by-step explanation:

To find the x coordinate of the vertex, we use the formula, -b / 2a. In this problem, a = 2, and b = -4. c is -5, but we don't need to know it.

- -4 / 2(2) = 4 / 4 = 1

Vertex = (1, y)

Next, we plug 1 back into the parabola equation for x to solve for y.

y = -2(1)^2 - 4(1) -5

y = -2^2 - 4 - 5

y = -4 - 4 - 5

y = -8 - 5

y = - 13

Vertex = (1, -13)