Question

How do you factor `3x^3 - 3x^2 - 60x`?

Answer 1

3x(x + 4)(x - 5)

Explanation:

`f(x) = 3xy = 3x(x^2 - x - 20)`
factor y, the trinomial in parentheses.
`y = x^2 - x - 20.`
Find 2 numbers knowing sum (b = -1) and product (c = -20). It is the sum (4, -5).
y = (x + 4)(x - 5)
Therefor,
f(x) = 3x(x + 4)(x - 5)