Question

Use elimination to solve for x and y: -2x-y=9 2x-9y=1

Group of answer choices A. (5, 1) B. (-1, -7) C. (-4, -1) D. (-1, -4)

Answer 1

C

Explanation:

Label the two equations:

-2x -y= 9 -----(1)

2x -9y= 1 -----(2)

(1) +(2):

-2x -y +2x -9y= 9 +1

-2x +2x -y -9y= 10

Simplify:

-10y= 10

y= 10 ÷(-10)

y= -1

Substitute y= -1 into (2):

2x -9(-1)= 1

2x +9= 1

2x= 1 -9

2x= -8

x= -8 ÷2

x= -4

Thus, the solution is (-4, -1).