Will award brainliest please help

Choice C)  

We can say 4*sqrt(21) as optional formatting

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Work Shown:

Note how I factored each value in the square root such that we had one factor as a perfect square. That is useful to break up the root using the rule

I introduced the variable y to help show how the terms combine. This step is optional.

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step-by-step explanation:

1. sometimes

2. never true

3. sometimes

step-by-step explanation:

these are pretty self explanatory if you know what supp right and com angles are