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 - Review Exercises - Page 497: 33

Answer

$\frac{3x^2+9x}{x^2+8x-33}$.

Work Step by Step

The given expression is $\Rightarrow \frac{\frac{2}{x^2-x-6}+\frac{1}{x^2-4x+3}}{\frac{3}{x^2+x-2}-\frac{2}{x^2+5x+6}}$ Factor each denominator as shown below. $\Rightarrow x^2-x-6$ Rewrite the middle term $-x$ as $-3x+2x$. $\Rightarrow x^2-3x+2x-6$ Group terms. $\Rightarrow (x^2-3x)+(2x-6)$ Factor each group. $\Rightarrow x(x-3)+2(x-3)$ Factor out $(x-3)$. $\Rightarrow (x-3)(x+2)$ $\Rightarrow x^2+x-2$ Rewrite the middle term $x$ as $2x-x$. $\Rightarrow x^2+2x-x-2$ Group terms. $\Rightarrow (x^2+2x)+(-x-2)$ Factor each group. $\Rightarrow x(x+2)-1(x+1)$ Factor out $(x+2)$. $\Rightarrow (x+2)(x-1)$ $\Rightarrow x^2-4x+3$ Rewrite the middle term $-4x$ as $-3x-x$. $\Rightarrow x^2-3x-x+3$ Group terms. $\Rightarrow (x^2-3x)+(-x+3)$ Factor each group. $\Rightarrow x(x-3)-1(x-3)$ Factor out $(x-3)$. $\Rightarrow (x-3)(x-1)$ $\Rightarrow x^2+5x+6$ Rewrite the middle term $5x$ as $3x+2x$. $\Rightarrow x^2+3x+2x+6$ Group terms. $\Rightarrow (x^2+3x)+(2x+6)$ Factor each group. $\Rightarrow x(x+3)+2(x+3)$ Factor out $(x+3)$. $\Rightarrow (x+3)(x+2)$ Back substitute all factors into the given expression. $\Rightarrow \frac{\frac{2}{(x-3)(x+2)}+\frac{1}{(x-3)(x-1)}}{\frac{3}{(x+2)(x-1)}-\frac{2}{(x+3)(x+2)}}$ The LCD of all the denominators is $(x-3)(x-1)(x+2)(x+3)$ Multiply the numerator and the denominators by $(x-3)(x-1)(x+2)(x+3)$. $\Rightarrow \frac{(x-3)(x-1)(x+2)(x+3)\left (\frac{2}{(x-3)(x+2)}+\frac{1}{(x-3)(x-1)}\right)}{(x-3)(x-1)(x+2)(x+3)\left (\frac{3}{(x+2)(x-1)}-\frac{2}{(x+3)(x+2)}\right )}$ $\Rightarrow \frac{2(x-1)(x+3)+1(x+2)(x+3)}{3(x-3)(x+3)-2(x-3)(x-1)}$ Use the FOIL method. $\Rightarrow \frac{2(x^2+3x-x-3)+1(x^2+3x+2x+6)}{3(x^2+3x-3x-9)-2(x^2-x-3x+3)}$ Simplify. $\Rightarrow \frac{2(x^2+2x-3)+1(x^2+5x+6)}{3(x^2-9)-2(x^2-4x+3)}$ Use the distributive property. $\Rightarrow \frac{2x^2+4x-6+x^2+5x+6}{3x^2-27-2x^2+8x-6}$ Add like terms. $\Rightarrow \frac{3x^2+9x}{x^2+8x-33}$.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.