D
First solve the second equation. Replace g (2) into that equation which just means replace 2 in the place of x. You should get f (3). Then, replace f (3) in the first equation which just means replace 3 in the x's.
(3 - 2)^3 (3^2 - 4) / 16
(1) (5) / 16
= 5/16
