Question

25(a+b)^2-9(a-b)^2

Answer 1

25(a+b)^2-9(a-b)^2

=[5(a+b)]^2-[3(a-b)]^2

=[5(a+b)+3(a-b)][5(a+b)-3(a-b)]

=[5a+5b+3a-3b][5a+5b-3a+3b]

=[8a+2b][2a+8b]

=2(4a+b)*2(a+4b)

=4(4a+b)(a+4b)