add 2 square root 21 + 3 square root 21

Answer 1

To add the two terms, 2√21 and 3√21, we add the coefficients in front of the square roots:

2√21 + 3√21 = (2 + 3)√21
= 5√21

So, 2√21 + 3√21 is equal to 5√21.