Solutions to an Irregular Binomial

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jramirez23

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Jan 23, 2008
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I understand the following question thoroughly, but I don't understand why my friend states that his answers are 0, 2, and -2 while mine are 2 and -2. I solved the equation using factoring.

x[sup:2qmwt9yj]3[/sup:2qmwt9yj] - 4x = 0

Would my friend be correct in stating 0 as an answer as well?
 
jramirez23 said:
I solved the equation using factoring.

x[sup:1ba18pcf]3[/sup:1ba18pcf] - 4x = 0

Would my friend be correct in stating 0 as an answer as well?
Click to expand...
Did you plug zero in for "x", and check the result?

When you factored, what did you get? (You should have had three factors!)

Please be complete. Thank you! :D

Eliz.
 
I was taught that a cubic has three roots, real or otherwise.
 
jramirez23 said:
I see that the Xs could also be zeros.
Click to expand...
The cubic factors as (x)(x - 2)(x + 2). Did you perhaps forget that the "x" is a factor, too, and "divide through"...?

Eliz.
 
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