Question

factorise : a(a-1)-b(b-1)

Answer 1

a(a-1)-b(b-1)
$a ^{2} - a - b {}^{2} + b$

Answer 2

$a {}^{2} - a - b {}^{2} + b$

$a {}^{2} - b {}^{2} + b - a$

$(a + b)(a - b) - (a - b)$

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


Thanks