Question

Factorise: (x+y)(a+b)+(x-y)(a+b)

Answer 1

(a+b)(x+y+x-y)
(a+b)(2x)
2x(a+b)

Answer 2

(x+y)(a+b)+(x-y)(a+b)

=(a+b)[x+y+x-y]

=2x(a+b)