Question

factorise {a^(2)-b^(2)-a-b}

Answer 1

to get the a^2 and b^2 you need both a times a and b times b and to get the a and the b you need a without coeffiecents you need a 1

(a    b)(a   b   1)

Now you just need to signs

a times a is a^2

a times b is ab

a times 1 is a

-b times a is -ab

-b times b is -b^2

-b times 1 is -b

Combine like terms. The ab and -ab cancel and you get:

a^2-b^2+a-b

(a-b)(a+b+1)

Answer 2

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