Question

How do you factor `3x^2 - 2x -21`?

Answer 1

`(3x+7)(x-3)`

Explanation:

`3x^2+7x-9x-21` find two integers that ADD to -2, MULTIPLY to -63 (`3*-21`)
`3x(x-3)+7(x-3)` factor out common factor
`(3x+7)(x-3)`