1. Adding and subtracting radicals. Add 3√21 + 7√21

Question

A. √24 + √28
B. √52
C. 10√42
D. 10√21

I have a feeling its d

Answer 1

You are correct!

To add the radicals, you add the coefficients and keep the same radical. So, 3√21 + 7√21 = (3+7)√21 = 10√21.

Therefore, the correct answer is D. 10√21.