Answer:
x = 6, y = -3
Step-by-step explanation:
x = -2y
x-y = 9
Substitute x = -2y into the equation.
;(-2y)-y = 9
-3y = 9
y = 9/-3
y = -3
Substitute y = -3 into the equation.
x = -2(-3)
x = 6