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Adding or subtracting quadratics

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Adding or subtracting quadratics

by doclkk » Wed Aug 05, 2009 8:00 am
In general

How do you add or subtract fractional quadratics

Example (not sure if will work)

[X^2+5x+6] / [X+2] - [X^2 + 4x +4] / [(x+2) (x-2)]

It was something like this and I foiled everything out but I guess I don't know the rules of hwat you can cancel and what you can't cancel?

thanks
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by truplayer256 » Wed Aug 05, 2009 8:11 am
[X^2+5x+6] / [X+2] - [X^2 + 4x +4] / [(x+2) (x-2)]

Well, get a common denominator first and factor the numerators.

(x+3)(x+2)(x-2)/[(x+2)(x-2)]-(x+2)(x+2)/[(x+2)(x-2)]

Factor out an x+2 since it's common to both fractions.

x+2[(x+3)(x-2)-(x+2)]/[(x+2)(x-2)]

The x+2's cancel and you're left with:

x^2+x-6-x-2/[(x-2)]

=x^2-8/x-2
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