1. Objective #19: Factor trinomials, ax(x + b)(x − c)
Easier example:
Always start by pulling out the GCF:
2x (x2 − x − 2)
Then factor the rest like you did in objective 17 or 18:
2x (x − 2)(x + 1)

2. Harder example:
Pull out the GCF: x2y(20x2 + 7xy − 3y2)
Factor the trinomial: factors have to multiply to −60 and add up to 7 (ans: −5 and 12)
Split middle term using those factors:
20x2 − 5xy + 12xy − 3y2
Pull out the GCF of the first 2 terms and the last 2 terms:
5x(4x − y) + 3y(4x − y)
Put it all together with the original GCF:
3x2y (5x + 3y)(4x − y)