Mark H. answered • 06/28/19

Tutoring in Math and Science at all levels

Another option:

First, recognize that every term is divisable by 3.

Thus:

3x^{2} + 6x - 24

becomes:

3 * (x^{2} + 2x - 8)

Next,find the factors of x^{2} + 2x - 8

The factors of -8 must have opposite signs, therefore +2 must be the __difference__ between 2 factors. -8 factors into -4 and +2, so we have:

(x + 4)(x - 2)

Bring in the 3 and we have:

3(x + 4)(x - 2)

Maria H.

Also, I still don't understand the third step, "Next, find the factors...." Could you explain it more if you can?06/28/19

Mark H.

It sounds like you need a review of the basics of factoring. Are you OK with concept when it comes to constants? e.g. the possible factor pairs for 12 are 1*12, 2*6, and 3*4. Also, the negative of each one--eg -1*-12 Expressions with unknowns have factors also. A simple example is x^2 -2 x This factors to x * (x + 2) Look at my solution for the factors of x^2 + 2x - 8. I got (x + 4) and (x - 2). Multiply these together to see that you get the expression I started with. To answer your other question: (x - 4)*(x + 2) = x^2 - 2x - 8 NOT the same thing, right? If this is all going over your head, you may want to sign up with a tutor.06/28/19

Maria H.

Thank you!07/02/19

Maria H.

I have another question. So one of the answers was the one that you came up with, however, there was another one that said 3(x - 4)(x + 2) I am wondering what the difference is06/28/19