Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 6 - Test - Page 499: 9

Answer

$\frac{5x^2-7x+4}{(x+2)(x-1)(x-2)}$.

Work Step by Step

First determine the Least Common denominator (LCD). Factor $x^2-4$. $\Rightarrow x^2-2^2$ Use special formula $A^2-B^2=(A+B)(A-B)$. $\Rightarrow (x+2)(x-2)$ Factor $x^2+x-2$. Rewrite the middle term $x$ as $2x-1x$. $\Rightarrow x^2+2x-1x-2$ Group terms. $\Rightarrow (x^2+2x)+(-1x-2)$ Factor each group. $\Rightarrow x(x+2)-1(x+2)$ Factor out $(x+2)$. $\Rightarrow (x+2)(x-1)$ Back substitute into the given expression. $\Rightarrow \Rightarrow \frac{5x}{x^2-4}-\frac{2}{x^2+x-2}=\frac{5x}{(x+2)(x-2)}-\frac{2}{(x+2)(x-1)}$ The LCD is $(x+2)(x-1)(x-2)$. Multiply the numerator and the denominator to form LCD at the denominators. $\Rightarrow \frac{5x(x-1)}{(x+2)(x-1)(x-2)}-\frac{2(x-2)}{(x+2)(x-1)(x-2)}$ Add numerators because denominators are same. $\Rightarrow \frac{5x(x-1)-2(x-2)}{(x+2)(x-1)(x-2)}$ Use the distributive property. $\Rightarrow \frac{5x^2-5x-2x+4}{(x+2)(x-1)(x-2)}$ Add like terms. $\Rightarrow \frac{5x^2-7x+4}{(x+2)(x-1)(x-2)}$.
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