Let f(x) = x^2 and g(x) = 2x, for all real x

Let f(x) = x² and g(x) = 2x, for all real x. Then the value of f(f(g(x)) + g(f(x))) at x = 1 is

1. 16
2. 18
3. 36
4. 40

Answer

f[f(2x) + g(x²)]

As x = 1,

f[f(2) + g(1)]

= f[2² + 2(1)]

= f[6]

= 6²

= 36

The correct option is C.