Factor 3a^2-2b-6a+ab

$3 a^{2} - 2 b - 6 a + a b$

Reorder terms.

$3 a^{2} - 6 a - 2 b + a b$

Factor out the greatest common factor from each group.

Group the first two terms and the last two terms.

$(3 a^{2} - 6 a) - 2 b + a b$

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

$3 a (a - 2) + b \cdot (a - 2)$

Factor the polynomial by factoring out the greatest common factor, $a - 2$ .

$(a - 2) (3 a + b)$