Answer:
a)

b)

Explanation:
To find an inverse function, follow these steps.
Step 1. Write the function.
Step 2. Replace the function name in function notation with y.
Step 3. Switch x and y.
Step 4. Solve for y.
Step 5. Replace y with function notation for inverse function.
Now let's do part a) following the steps above.
Step 1.

Step 2.

Step 3.

Step 4.




Step 5.

Now let's do part b) following the steps above.
Step 1.

Step 2.

Step 3.

Step 4.




Step 5.
