Question

Find the solution to the system of equations given below using substitution.

A. x = -1, y = -7
B. x = 7, y = -1
C. x = 7, y = 1
D. x = -1, y = 7

Answer 1

Hello!

The answer is:

D.

`x=-1\\y=7`

Why?

Substitution method for solving system of equations consists in isolate one variable in terms of the other variable.

So, isolating x in terms of y from the second equation, we have:

`x-8y=-57\\x=-57+8y`

Then, substituting x into the first equation, we have:

`2(-57+8y)+3y=19\\-114+16y+3y=19\\20y=19+114\\19y=133\\y=(133)/(19)=7`

Now, substituting y into the second equation we have:

`x-8(7)=-57\\x-56=-57\\x=-57+56=-1`

Have a nice day!

Answer 2

Answer: OPTION D

Explanation:

You can apply the SUBSTITUTION method:

- Solve for x from the second equation and substitute it into the first equation.

- Solve for y:

`x-8y=-57\\x=-57+8y`

`2(-57+8y)+3y=19\\-114+16y+3y=19\\19y=133\\y=7`

- Substitute y=7 into any of the original equations ans solve for x. Then:

`x-8(7)=-57\\x-56=-57\\x=-57+56\\x=-1`