Question

Factorise 1 - 3x-3y-4(x+y)square

Answer 1

1-3(x+y)-4(x+y)^2

=1+(x+y)-4(x+y)-4(x+y)^2
=1[1+(x+y)] -4(x+y)[1+(x+y)]

=[1+(x+y)]{1-4(x+y)}
=(1+x+y)(1-4x-4y)

Answer 2

1-3(x+y)-4(x+y)^2

=1+(x+y)-4(x+y)-4(x+y)^2

=1[1+(x+y)] -4(x+y)[1+(x+y)]

=[1+(x+y)]{1-4(x+y)}

=(1+x+y)(1-4x-4y)