Question

How do you factor completely `3x^2 - 9x - 30`?

Answer 1

Divide the whole equation by 3 to simplify:

`3x^2-9x-30=x^2-3x-10`

Find factors of `10` : `1,2,5,10`):
`2` and `5` work to make `10` and `3`

Therefore,

`(x+2)(x-5)`

Do not forget to add the three back!

`3((x+2)(x-5))`

So you would multiply out the brackets first, then the result should be `x^2-3x-10`. Multiply all factors out with `3` and this should give you `3x^2-9x-30`