f (x) = x^2 + d and g (x) = 2x^2, where d is a constant.

If f (g (2))/f (2) = 4, what is the value of d?

2*2^2 /(2^2+d) = 4.

8/(4+d) = 4,
16 + 4d = 8,
d = -2.