Question

Factorise
1-2a-2b-3(a+b)²​

Answer 1

1-2a-2b-3(a+b)²

= 1-2(a+b)-3(a+b)²

= 1- 3(a+b) +(a+b) -3(a+b)²

= 1[1-3(a+b)]+(a+b)[1-3(a+b)]

= [1-3(a+b)][1+(a+b)]

= (1-3a-3b)(1+a+b)