Question

(a-b)(1-a-b ) of factorisation

Answer 1

1(1 - ab) + b(ab - 1) = 1[(-1)(ab - 1)} + b(ab -1)
 = [1(-1)}(ab - 1) + b(ab - 1)
 = -1(ab - 1) + b(ab - 1)
 = (- 1 + b)(ab - 1)
 = [b + (-1)](ab - 1)
 = (b - 1)(ab - 1)please mark as brainlist answer