MR-95 / 230b. problem

Simplify the following expression:

6-42

6-42

=6-422

=6-32

a±b=a+a2-b2±a-a2-b2

a=6 ; b=32

6-32

=6+62-322-6-62-322
=6+36-322-6-36-322
=6+42-6-42
=6+22-6-22

=82-42

=4-2

=2-2