# Math Help - Am I expanding this correctly?

1. ## Am I expanding this correctly?

Did very good on my last test, so I'll have to keep coming here for advice

How would I expand:

(x-3)(x+5)(3x+6)

Is it:

x2 - 5x +3x2 + 6x -3x - 15 -9x - 18

4x2 - 11x - 33 ?

2. ## Re: Am I expanding this correctly?

You need to expect that the product of 3 linear factors will be a cubic expression. You should get:

$3x^3+12x^2-33x-90$

3. ## Re: Am I expanding this correctly?

Ah I see how you did that now.

Thanks for clarifying.