Factor a-b+ab-1

$a - b + a b - 1$

Step 1

Regroup terms.

$a b + a - b - 1$

Step 2

Factor out the greatest common factor from each group.

Group the first two terms and the last two terms.

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

Factor out the greatest common factor (GCF) from each group.

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

Step 3

Factor the polynomial by factoring out the greatest common factor, $b + 1$ .

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