Evaluating/Simplifying an Expression

[kingzero]

Part f. is the only expression I am unsure of what steps to take to get the correct answer.

Would anyone be willing to give me an idea?

 

[kingzero]

I went ahead and tried it, but I'm still uncertain if I am on the right track.

 

[HallsofIvy]

Why did you stop at $$\frac{4h}{x+ h- x}$$? You are aware that x+ h- x= h, aren't you?