Question

I a trying to find a GCF to factor out this quadratic equation, can you help?

0 = -x^2 + 2x + 15

Answer 1

@mathstudent55

Answer 2

What is something that will go into every term in your equation?

Answer 3

Excuse my mentality, I have been doing these right for the past half hour but I guess my mind decided to troll me on this question *facepalm*

Answer 4

Thanks for bringing me to senses, also would it be -x because I have never seen -x before :/ @eSpeX

Answer 5

You are on the right track and I apologize if I came across as condescending.
Your last term does not have a 'x' in it though...

Answer 6

No your fine :), oh and the way the lesson taught me is to just do this when there is no GCF:
(x +/- #)(x +/- #)

Answer 7

Wait, grrr I am wrong, I am trying to find the GCF of 2 and 15 my bad

Answer 8

Rather than try a -x, which as we said does not exist in every term, what about -1?

Answer 9

GCF or are you factoring?

Answer 10

Yes but then the product would be negative and so it would be wrong right? Since 15 is positive and so is 2

Answer 11

I need to find two numbers that the sum is 2 and the product is 15

Answer 12

No, you are correct, and so what multiplies together to create -15 and adds together to get -2?

Answer 13

The original equation is:
x^2 = 2x + 15

Answer 14

Well in that case it would be +5 -3

Answer 15

nono -5 +3

Answer 16

I would have pushed everything to the left as to keep my square positive. And +5-3=+2

Answer 17

Exactly. Good job. So your final result is?

Answer 18

(x + 3)(x - 5)
x + 3 = 0 OR x - 5 = 0
-3 -3 +5 +5
x = -3 AND x = 5

right?

Answer 19

Yes, that is right.
I would point out though that what you have done is considered "factoring" and not finding the GCF. :)

Answer 20

Yes me and correct terminology do not get along xD but I usually understand it that way in my head but thanks :D

Answer 21

You're welcome. Best of luck.

Answer 22

Thanks.