Question

WORTH 20 POINTS

according to the system of equations below what is the value of x? x+y=-9, x+2y=-25

Answer 1

x + y = -9
y = -x - 9

x + 2y = -25
2y = -x - 25
——————
2
y = -1/2x - 12.5

-x -9 = -1/2x - 12.5
-x + 1/2x = -12.5 + 9
-1/2x = -3.5
——————
-1/2
x = 7

1) turn the equations into y = mx + b
2) equal the two together (just mx + b)
3) solve for x

*watch for signs when switching sides*

:)