Since you don't need the full answer, here are a couple hints:
- dy/dx is the first derivative
- (d²y) / (dx²) is just the second derivative
- The subscript "x=1" means to find the derivative when x is 1
- X is function of x
- Plug in X into (X² + 3)², the result should be in terms of x
- If the derivatives were calculated properly, the last part of the question should be able to be proved easily.
I hope these tips help