Question

A variable needs to be eliminated to solve the system of equations below. Choose the

correct first step.
-3x - 9y = 36
X - 9y = 12

Answer 1

Two different things u can do
Substitution:
X-9y=12
+9y +9y
X=9y+12

-3(9y+12)+9y=36
-27y-36+9y=36
+36 +36
-18y = 72
/-18 /-18
Y = -4


Or whatever this other I’ve is called

-3x-9y=36
-1(X-9y)=(12)-1

-3x-9y=36
-x+9y=-12

-4x=24
X= -6