=√3/√7

=√3*√7/√7*√7

=√2 1/7

12 of a branch with 7 roots minus 3/7 roots.

=( 12-3)/√7

=9/√7

=9√7/√7*√7

=9√7/7

You can ask if you don't understand! Satisfied, please adopt it in time! O(∩_∩)O