Question

Factor by grouping

Answer 1

When I factor is out I got x^2(x+3x)+8(x+9) but then I'm not sure what to do next or if I'm on the right track

Answer 2

@jim_thompson5910

Answer 3

Before you factor out, you would be wise to examine a little.
\(x^3+9x^2+8x+72\)
Did you notice that the ratio between the first and second terms is 1:9, same as that between 3rd and 4th 8:72=1:9
So extracting \(x^2\) from the two terms gives you:
\(x^2(x+9) + 8(x+9)\)
Can you take it from here?

Answer 4

@vshiroky
Do you need further help?

Answer 5

I don't think I did it right.
(x^3+9)(x+9)

Answer 6

@mathmate

Answer 7

Wait wait..... (x+9)(x^2+8)

Answer 8

Would this help?
\(x2\color{red}{(x+9)}+8\color{red}{(x+9)}\)

Answer 9

Red is one factor, and black is the other factor.

Answer 10

Typo, forgot exponentiation:
\(x^2\color{red}{(x+9)}+8\color{red}{(x+9)}\)

Answer 11

So I didn't do it right? lol

Answer 12

Your first factorization (x^2) was not correct.

Answer 13

poop

Answer 14

It should have been
\(x^2(x+\color{red}{9})+8(x+9)\)

Answer 15

That's as simple as I can make it?

Answer 16

I had that.. I was trying to make it more simple lol

Answer 17

You need to go through a second factorization, which is almost done for you.
The red factor is a common factor, so extract that, you will get the final answer.

Answer 18

this:
\(x^2\color{red}{(x+9)}+8\color{red}{(x+9)}\)

Answer 19

What do you mean extract it?
Like
(x^3+9)(x+8)

Answer 20

I don't know why I'm not understanding

Answer 21

Almost, the red factor is (x+9), so you just write
\(\color{red}{(x+9)}(x^2+8)\)

Answer 22

Lol I wrote that up above

Answer 23

But not (x^3+9) ...:(

Answer 24

I had changed it where I wrote wait wait..... haha

Answer 25

and it should be (x^2+8) for the other one.

Answer 26

Thank you :)

Answer 27

You're welcome! :)