Use substitution to solve the system of equations.
2x+y=-7
-5x+2y=22
A. (–36, 65)
B. (–4, 1)
C. (8, –23)
D.
(36, –79)

Question

Use substitution to solve the system of equations.
2x+y=-7
-5x+2y=22
A. (–36, 65) 
B. (–4, 1) 
C. (8, –23) 
D. 
(36, –79)

igreen · Answer

Rearrange and substitute:

$2x + y = -7$

$2x = -y - 7$

$x = -1/2y - 7/2$

Substitute:

$-5x + 2y = 22$

$-5(-1/2y - 7/2) + 2y = 22$

Distribute -5 into the parenthesis:

$2.5y + 17.5 + 2y = 22$

Subtract 17.5 from both sides:

$2.5y + 2y = 4.5$

Combine like terms:

$4.5y = 4.5$

Divide 4.5 to both sides:

$y = 1$

igreen · Answer

Our $y$ value is 1. And there's only one choice with the y-value of 1. So your answer is C.

igreen · Answer

So your answer is B*

anonymous · Answer

Thanks again. what about this one??

anonymous · Answer

Which of the following is not a solution to the system of linear equations below? 
x-2y=4
-2x+4y=-8

A. 

(2, –1) 


B. 

(4, 0) 


C. 

(0, 2) 


D. 

(6, 1)

igreen · Answer

C