Multiplying Rational Epressions

[XxBubbleGummxX]

HELP! I'm doing a math assignment and Im completely LOST.
This is our question.

4xcubed-36x/8x-24 * 2xsquared+6x/4xsquared+12x

To tell the truth I dont even know where to start...

 

[stapel]

Im completely LOST.

4xcubed-36x/8x-24 * 2xsquared+6x/4xsquared+12x

To tell the truth I dont even know where to start...

The place to start would be to learn the necessary background material. At a guess, you need to learn about simple factoring, factoring quadratics, special factoring, multiplying polynomials, and simplifying rational expressions. Obviously, we can't provide the hours of classroom instruction necessary to provide you with this lesson instruction. Would you like links to online lessons for these topics? If so, are there any other topics you think you probably need, too? Thank you!

 

[XxBubbleGummxX]

Well I know how to factor... My teacher told us you always do that first, but I dont know where to go or what to do after that.

 

[stapel]

Im completely LOST.... I dont even know where to start...

Well I know how to factor... My teacher told us you always do that first, but I dont know where to go or what to do after that.

Oh, okay; so you were not actually "completely lost" and did actually "know where to start". Kindly please note that your first post gave a different impression.

Please reply showing your factorization, including any cancelling you did after you factored. Thank you!

 

[XxBubbleGummxX]

Well I did the factoring and this is what I came up with.

4(x^3-9x)/4(2x-6) * 2x(x+3)/2x(2x-6)

And I cant figure out what to do now :/

 

[stapel]

Well I did the factoring and this is what I came up with.

4(x^3-9x)/4(2x-6) * 2x(x+3)/2x(2x-6)

And I cant figure out what to do now :/

Okay, so the first step is to learn how to factor polynomial expressions.

To learn how to factor the \(\displaystyle 4x^2\, +\, 12x\) (which is simple factoring), try here.

After you've learned that, you can correctly begin the factorization of, for instance, \(\displaystyle 4x^3\, -\, 36x\). Then, to learn how to factor the \(\displaystyle x^2\, -\, 9\) that's left (which is a difference of squares), try here.

If you get stuck, or if you're unsure of your result, please reply showing all of your steps. Thank you!

 

[XxBubbleGummxX]

because (x^2-9) is a difference of squares, its can be factored down into (x-3)(x+3). So I ended up with 4x(x+3)/8 * 2x/4x..... Im thinking that I can cancel out the 4x's, unless I have to factor 2x / 4x?

 

[XxBubbleGummxX]

Geezzz BG, you're evidently unaware of the basics.
And it's almost impossible to conduct a classroom here.
Have you missed math classes?

Im aware that Im not the smartest person but I havent missed any classes. I just dont understand the material. At all. It's like my brain wont retain any of the information.