Is there any other way to explain how roots work?

On page 105, in Addition and Subtraction topic -- where no. 2 and 8 came from?

Please explain the Roots Drill 1-7.

Thank you so much.

Can you tell me specifically what part of this is confusing you?

As I look at the drills, I see:
#1. 2*sqrt5 + 3*sqrt5 * sqrt5.
If we treat "sqrt5" like an "x" when we have 6x. Since it's really sqrt5, we have 6*sqrt5.

Can you help me understand where you're struggling with these so that I can be more specific in my explanation for you?

Thanks,
Veritas Help