Answer:
See below. 
Step-by-step explanation:
1)
So we have the limit: 

This is equivalent to: 

To solve, we can use the following property: 

Therefore, our limit is the same as: 

We are already given that the limit as x approaches 4 of g(x) is -2. Therefore: 

You simply need to evaluate this to solve the limit. I don't have enough information to solve this, so maybe you have something more. 
Similarly, for the second one: 
2)
We have: 

Using the same property: 

And we are told that this is 16, so: 

And we just need to evaluate this to find the limit. 
I hope you find this helpful!