If 2x^{2}-dx+(31-d^{2})x+5 has a factor of x - d, what is the value of d if d is an integer? (Crying)

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- Oct 28th 2012, 12:51 PMfirefox0903Can someone help me with this pre-Calculus question?
If 2x

^{2}-dx+(31-d^{2})x+5 has a factor of x - d, what is the value of d if d is an integer? (Crying) - Oct 28th 2012, 12:58 PMMarkFLRe: Can someone help me with this pre-Calculus question?
Let:

$\displaystyle f(x)=2x^2-dx+(31-d^2)x+5$

If $\displaystyle f(x)$ has a factor of $\displaystyle x-d$ then $\displaystyle f(d)=0$.

Hint: use the rational roots theorem on the resulting cubic in $\displaystyle d$. - Oct 28th 2012, 01:03 PMskeeterRe: Can someone help me with this pre-Calculus question?
post problems in the precalculus forum please.

- Oct 28th 2012, 01:17 PMfirefox0903Re: Can someone help me with this pre-Calculus question?
so if f(d)=0 then then the new f(x) is 2x^2+31x+5??

- Oct 28th 2012, 03:08 PMMarkFLRe: Can someone help me with this pre-Calculus question?
No, that doesn't mean to let d = 0, that means when x = d, f(x) = 0.