Answer:
Greetings!
The answer to the first image is: 3

The second image is 4

Explanation:
Here's how to rationalize a denominator:
1. Multiply numerator and denominator by a radical that will get rid of the radical in the denominator.
2. Make sure all radicals are simplified.
3. Simplify the fraction if it is needed.
I hope this helps you! :)