Question

Simply the problem.

Answer 1

3√7

Explanation:

√3×√21=√63

√63=√7×√9=√7 × 3

=3√7

Answer 2

C

Explanation:

`√(3)\cdot√(21)= \\\\√(3\cdot 21)= \\\\√(63)= \\\\3√(7)`

Therefore, the correct answer is choice C. Hope this helps!