Answer:
(C) 16
Step-by-step explanation:
Subtract the second equation from the first equation.
9x + 2y^2 - 3z^2 = 132 minus 9y + 2y^2 - 3z^2 = -12
9x + 2y^2 - 3z^2 = 132
-(9y + 2y^2 - 3z^2 = -12 )
This will change all the signs of the second equation.
9x + 2y^2 - 3z^2 = 132
-9y - 2y^2 + 3z^2 = +12
You have left 9x - 9y = 144.
Factor out the 9 so you have 9(x - y) = 144
Divide both sides by 9
x - y = 16
