Factoring Polynomials

zee-f · 2011-07-21 09:36:47

i showed what i did

x^2-3x-18=
x^2-6x-3x-18

x(x-6)-3(x-6)

(x-3)(x-6)

bobbym · 2011-07-21 09:41:09

-6 x - 3 x = -9 x not -3 x

zee-f · 2011-07-21 09:44:03

dont i have to factor x^2-6x
i used the method anonimnystefy used

bobbym · 2011-07-21 09:49:04

Yes, but you have to group so that it so that it still equals the original polynomial.

x^2-6x-3x-18 does not equal x^2-3x-18

bobbym · 2011-07-21 10:35:15

Hi zeef

Try this grouping:

x^2 + 3x - 6x - 18

zee-f · 2011-07-21 10:46:01

thats ganna give me

x(x+3)-3(2x-6)

bobbym · 2011-07-21 11:25:12

Hi;

Not exactly, do it this way:

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

( x + 3 ) ( x - 6 ) is the factorization.

Bob · 2011-07-21 19:49:42

hi zee-f

You wrote:

does anybody know a good website that teaches you Factoring Polynomials using grouping

and bobbym wrote:

I can not think of a better one than here.

Of course I agree with this ... and who better to help than bobbym.

But, having said that you might like to look at

http://www.youtube.com/watch?v=2Q8lG1WaqJY

There are three examples there that take you through a prescriptive method using grouping.

Bob

Last edited by Bob (2011-07-21 19:52:46)

zee-f · 2011-07-22 09:48:52

ok so this is what the question says Factor problems 9 - 12 by using the difference of squares method. what on earth does that mean ????

bobbym · 2011-07-22 09:56:05

Hi bob bundy;

and who better to help than bobbym

Yikes! Let me tell you about him. Took two bullets straight through his head in 67. Yes clean through, nowadays people use his head in place of binoculars. I mean should we listen to a guy who the wind does not have to go around his head?

Hi zee-f;

Can you please bring those problems down here? Did you watch bob bundy's video?

zee-f · 2011-07-22 10:02:04

yup i willl but i dont just want the answer i want help on the method plz

9. x^2 4

AThis polynomial cannot be factored by using the difference of squares method.
B(x 2)(x 2)
C(x 2)(x 1)
D(x 2)(x + 2)
E(x 1)(x 4)
F(x + 2)(x + 2)

bobbym · 2011-07-22 10:09:45

Hi;

I like D) here is why.

http://www.mathsisfun.com/algebra/speci … ducts.html

http://www.mathsisfun.com/algebra/factoring.html

And then go here and you will know as much about it as I do!

http://regentsprep.org/REgents/math/ALG … factps.htm

zee-f · 2011-07-22 10:26:48

thanx allllot am ganna see the links and do the rest of the problems ill submit my answers tomorrow to make sure thanx allot guyyys

bobbym · 2011-07-22 10:28:34

Okay! I will wait to see your answers. And please watch the video! I am watching it now.

Bob · 2011-07-22 21:12:55

hi zee-f

Difference of two squares.

When there is no 'x' term, it has disappeared because there was a plus term and a minus term that cancelled out. (see picture)

That leaves an x squared term and a minus term, which will also be a perfect square. (in my diagram '4' is a perfect square because it is 4 = 2 x 2 )

So you have the difference of two squares, x squared and two squared.

Does that help you to see which answer MUST be correct?

Bob

zee-f · 2011-07-23 01:08:05

hey guys thanx allot for all this help and sources it helped me solve my problems this is what i got

for #9 i got d and 10-D 11-E 12-D
Factor problems 9 - 12 by using the difference of squares method.

9. x^2 4

AThis polynomial cannot be factored by using the difference of squares method.
B(x 2)(x 2)
C(x 2)(x 1)
D(x 2)(x + 2)
E(x 1)(x 4)
F(x + 2)(x + 2)

10. x^2 25

A(-x 5)(x - 5)
BThis polynomial cannot be factored by using the difference of squares method.
C(-x + 5)(x + 5)
D(x 5)(x + 5)
E(x + 5)(-x - 5)
F(x 5)(x - 5)

11. 36x^4 4x^2

A(6x^2 2x)(6x^2 - 2x)
B(6x^2 + 2x)(6x^2 + 2x)
CThis polynomial cannot be factored by using the difference of squares method.
D(-6x^2 2x)(-6x^2 - 2x)
E(6x^2 2x)(6x^2 + 2x)
F(-6x^2 + 2x)(6x^2 - 2x)

12. x^2 + 100

A(x + 10)(x 10)
B(-x + 10)(x 10)
C(x + 10)(x + 10)
DThis polynomial cannot be factored by using the difference of squares method.
E(x - 10)(x 10)
F(-x + 10)(-x 10)

anonimnystefy · 2011-07-23 01:10:19

all is correct.good job.

zee-f · 2011-07-23 01:14:31

thanx to u guys i got them correct thanx allot

zee-f · 2011-07-23 01:16:03

i was wondering is the perfect squares method different from this method ?

bobbym · 2011-07-23 01:16:10

Hi zee-f;

You did well!

zee-f · 2011-07-23 01:17:54

thanx bobbym

bobbym · 2011-07-23 01:21:28

Did you get around to watching that video?

zee-f · 2011-07-23 01:22:28

the grouping video yup it was really good he made the method reallly easy

bobbym · 2011-07-23 01:22:59

Yes, I watched it too and liked it.

zee-f · 2011-07-23 01:37:04

do u have any good links on the perfect squares method isn't like different from the difference of squares method.

Math Is Fun Forum

#26 2011-07-21 09:36:47

Re: Factoring Polynomials

#27 2011-07-21 09:41:09

Re: Factoring Polynomials

#28 2011-07-21 09:44:03

Re: Factoring Polynomials

#29 2011-07-21 09:49:04

Re: Factoring Polynomials

#30 2011-07-21 10:35:15

Re: Factoring Polynomials

#31 2011-07-21 10:46:01

Re: Factoring Polynomials

#32 2011-07-21 11:25:12

Re: Factoring Polynomials

#33 2011-07-21 19:49:42

Re: Factoring Polynomials

#34 2011-07-22 09:48:52

Re: Factoring Polynomials

#35 2011-07-22 09:56:05

Re: Factoring Polynomials

#36 2011-07-22 10:02:04

Re: Factoring Polynomials

#37 2011-07-22 10:09:45

Re: Factoring Polynomials

#38 2011-07-22 10:26:48

Re: Factoring Polynomials

#39 2011-07-22 10:28:34

Re: Factoring Polynomials

#40 2011-07-22 21:12:55

Re: Factoring Polynomials

#41 2011-07-23 01:08:05

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#42 2011-07-23 01:10:19

Re: Factoring Polynomials

#43 2011-07-23 01:14:31

Re: Factoring Polynomials

#44 2011-07-23 01:16:03

Re: Factoring Polynomials

#45 2011-07-23 01:16:10

Re: Factoring Polynomials

#46 2011-07-23 01:17:54

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#47 2011-07-23 01:21:28

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#48 2011-07-23 01:22:28

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