Whatever is inside parentheses first [g(x)], is what you would evaluate first, then after that, you would substitute that answer into the f(x) function for EVERY "X" YOU SEE:
[2x² + 5]² + [2x² + 5] + 2
[2x² + 5]² + [2x² + 7]↓
This is your final answer. You get it?