Use your exponent rules.

This is also good for the square root question.

For example:

As far as the angle between the vectors...

Have you met the "Vector Inner Product"? Perhaps we should use the method of slopes? There are a few ways to go about it.

On the last, is the exponent "0" just a typo? Perhaps you meant ? In any case, just solve it.

-2sin(x) + 3 = 4

-2sin(x) = 1

sin(x) = -1/2

You should know values of x that have this sine value. Think "Quadrant" before you believe you are done.