more questions on simple harmonic motion

Could someone check these for me? i was told to put g = 9.8 m/s for all calculus questions, and I think it's a bit ridiculous.

**1. A long jumper running at 8 m/s jumps into the air, rising to a height of 0.7 metres. What is the length of the jump. **

maximum height

Range

**This is wrong. the answer says 5.29 m. **

**2. The velocity of a point moving along the x axis is given by **

**Show that it is simple harmonic.**

However this is not the form

so how would I do this?

Thanks!!! (Rofl) You guys are really helpful!