Question

factor this quadratic, x^2-10x+9

Answer 1

-x-9x=-10x
-9(-1)=9
so we can factor it like this:
(x-9)(x-1)

Answer 2

thank you

Answer 3

but now how do u do this? x^2+3x-10

Answer 4

5x-2x=3x
5(-2)=-10
so we can factor like this:
(x+5)(x-2)
make sense?

Answer 5

hmm okay i know ur right, but im just not understanding your first step? how do u get 5x-2x=3x sorry im new to this class lol

Answer 6

Well what you have to do is figure out what will work for you to end up with both the 3x and the -10. Since -2x+5x (or 5x-2x) equals 3x, and if you multiply -2 by 5 it gives you -10, those are the values to use when factoring it.

Sorry, I'm not very good at explaining :)

Answer 7

ehh sort of

Answer 8

x^2+4x-12 what about this one? O.o

Answer 9

Think about your factor of twelve: 2, 3, 4, 6...

It's kind of like process of elimination. 4*3 is 12, but 4-3 doesn't equal four, nor does 3-4. So try something else. 2*6=12, 2-6 doesn't equal four, but 6-2 does!

So we need two x's since it's x^2

(x )(x )

Since 2*6 is 12, these number go on the outside.

(x 2)(x 6)

Since 12 is negative in this problem, either 2 or 6 needs to be negative (since a negative*positive=negative)

(x-2)(x+6)

If we work it out:
x*x+6x-2x-12
x^2+4x-12

we see that it works!

Answer 10

factors*

Answer 11

Hopefully that's a better explanation...

Answer 12

yeah thanks :)

Answer 13

x^2-2-12 this one i dont get i put (x-3)(x-4) its incorrect apparently

Answer 14

Is that supposed to say 2x? Like x^2-2x-12?

Answer 15

no its saying to the 2nd power

Answer 16

Oh, so is it \[x^2-12\]

Answer 17

its x^2-2x-12

Answer 18

Oh. Hmmm... That's impossible to factor. Is that one of your options?

Answer 19

thats the eqiation

Answer 20

oh crap im sorry, its x^2-x-12

Answer 21

Oh, that makes more sense :)

Your answer is so close! But remember to get a negative number, like -12, one of the outside number needs to be positive and the other negative. So make it (x-3)(x+4) and that should be your answer :)

Answer 22

Actually wait. In this one, order matter. 4 has to be the negative one. (x+3)(x-4) is your answer.

Answer 23

matters*

See, this is the importance of checking your answers afterward lol

Answer 24

x*x-4x+3x-12
x^2-x-12

Answer 25

thanks thats right, :) so then how would we do this one 10x^2+31x+15

Answer 26

Okay, so let's start with 10.

The only factors of 10 are 5 and 2 (and technically, 1, but we're going to forget about that). So, 2x and 5x will be put on the left since 2x*5x=10x^2

(5x )(2x )

Now, let's look at 15.

The only factors of 15 are 3 and 5 (forgetting about 1 again). So, 3 and 5 need to go on the outside so we can achieve the "+15" part of the equation.

(5x 3)(2x 5)

Now, for 31. 31 is positive, so

(5x+3)(2x+5)

As always, we need to check it to make sure everything is in the right order :) As luck would have it, this works out without us having to really figure out how to get 31.

5x*2x+25x+6x+15
10x^2+31x+15

Answer 27

Sorry, but I have to go. If you have other struggles, bump your question or create a new one and maybe someone else can help you :) Good luck!

Answer 28

okay thank u girl!