Answer:

Explanation:
When you have exponents above a like term and they are being multiplied together, you add them. 
For example:

So let's group like terms in the numerator:
 
 We can add terms like in the example.

Let's rearrange the denominator.

Now we have: 
 Cancel like terms
4/8 = 1/2 
 = 1 So it cancels
 = s Since s is raised to the -1 it goes on top and becomes s.

Now we combine everything back together:
