Question

How do you factor `7x^3 - 21x^2 - 2x + 6` by grouping?

Answer 1

`(x - 3)(sqrt7x - sqrt2)(sqrt7x + sqrt2)`

Explanation:

`f(x) = 7x^2(x - 3) - 2(x - 3)`
`f(x) = (x - 3)(7x^2 - 2)`
`f(x) = (x - 3)(sqrt7x - sqrt2)(sqrt7x + sqrt2)`