Factors of a2−b+ab−a are
(a -b)(a + 1)
(a + b)(a - 1)
(a - b)(a - 1)
(a + b)(a + 1)
a2−b+ab−a=a2−a−b+ab = a(a-1)+b(-1+a) = a(a-1)+b(a-1) = (a+b) (a-1)
The factors of a2+b−ab−a are :