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September 2nd, 2016, 03:39 AM   #1
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Having trouble with factoring equations

I've checked many videos and really can't find any covering the equations i'm stuck with.

3xsquared -15x = 0

4xsquared -8x = 0

5xsquared -12x = 0

I understand an equation with two numbers such as xsquared -9x -10 = 0 a lot more than when theres only one number in the equation, as I would normally just find the sum of -9x and the product of -10... I can't do that with just one number from what I can see.

Any help would be much appreciated!
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September 2nd, 2016, 04:33 AM   #2
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Quote:
Originally Posted by WarmCustard View Post
I've checked many videos and really can't find any covering the equations i'm stuck with.
Interesting. I went to YouTube, typed in "factoring polynomials" and in less than a second got over 39,000 hits. The first two had problems just like the ones you are asking about.
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September 2nd, 2016, 05:19 PM   #3
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$3x^2 - 15x = 0 \implies 3x(x - 5) = 0 \implies WHAT?$
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September 2nd, 2016, 07:44 PM   #4
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It's really a quadratic:
3x^2 - 15x + 0 = 0
c = 0. Try it!
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September 3rd, 2016, 06:11 AM   #5
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Well you can still solve the equation...
Just like JeffM1 show

3x^2-15x=0
You can take 3x out of the equation
--> 3x(x-5)=0
3x=0
-> x=0;
x-5=0
-> x=5
Hence x=0 or x=5


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October 5th, 2016, 11:40 PM   #6
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3x^(2)−15x=0⟹3x(x−5)=0⟹x=0,x=5
4x^(2)− 8x=0⟹4x(x−2)=0⟹x=0,x=2
5x^(2)−12x=0⟹x(5x−12)=0⟹x=0,x=12/5

Last edited by rahuljoshi; October 5th, 2016 at 11:47 PM.
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October 18th, 2016, 03:48 PM   #7
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How to Factor

Always try to take out a GCF (biggest factor that they have in common)
In this case it's 3x
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