I'm realy stuck to the attached question I know how to do synthetic and long division, and that the remainder is just the value of the function after plugging in x.

help would be greatly appreciated. thanks.

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- Jul 2nd 2012, 07:17 PMwaleedrabbaniFactor theorem to find variable
I'm realy stuck to the attached question I know how to do synthetic and long division, and that the remainder is just the value of the function after plugging in x.

help would be greatly appreciated. thanks. - Jul 2nd 2012, 07:31 PMrichard1234Re: Factor theorem to find variable
The remainder of $\displaystyle \frac{f(x)}{x+2}$ is $\displaystyle f(-2)$, or $\displaystyle 4 - 2k$

The remainder of $\displaystyle \frac{f(x)}{x-2}$ is $\displaystyle f(2)$, or $\displaystyle 20 + 2k$

4-2k is twice that of 20+k, so $\displaystyle 4-2k = 2(20+2k) \Rightarrow k = -6$.