Question

Factor -7x^3+21x^2+3x-9 by grouping

Answer 1

`(-7x^2+3)(x-3)`

Explanation:

We can take "common" from first 2 terms and common from next 2 terms. Shown below:

`-7x^3+21x^2+3x-9\\-7x^2(x-3)+3(x-3)\\(-7x^2+3)(x-3)`

That's how we do it. We can't simplify, or factor, any further.