Question

How do you factor `3x^2 + 9x - 12 = 0`?

Answer 1

(x - 1)(3x + 12)

Explanation:

`y = 3x^2 + 9x - 12`
Since a + b + c = 0, use shortcut.
The 2 factors are (x - 1) and `(x - c/a = x + 12/3)`
`y = 3(x - 1)(x + 12/3) = (x - 1)(3x + 12)`