Answer:
C. 1/2
There are many ways to do this but I'll use substitution.
Step-by-step explanation:
Bottom equation yields x = 4 - 8y
plug that into the top equation results in:
4(4 - 8y) - y = 3y + 7
Simplify this to find y:
-36y = -9
y = 1/4
Plug that into the bottom equation we get:
x = 4 - 2 = 2
Thus, xy = 2(1/4) = 1/2 (C)
