Question

Solve the system of equations x - y = 12 and x + 7y = -20 by combining the
equations.

Answer 1

x=16, y=-4

Explanation:

-1(x-y=12)

x+7y=-20

-x+y=-12

x+7y=-20

8y=-32

y=-4

x-4=12

x=16

Answer 2

x= 8, y= -4

Explanation:

You can subtract one equation by another to eliminate x

(x-y)-(x+7y)=12-(-20)

-8y = 32

y= -4

Substitute y = -4 in the first equation:

x-(-4) = 12

x =8