Question

Please Help me with the problem below. its on the comment box thank you.

Answer 1

( (x-3) - y ) * ( (x-3) + y )
Let (x-3) = a
(a - y) * (a + y) = a^2 - y^2
Put (x-3) back in the place of a:
(x-3)^2 - y^2
Expand (x-3)^2