Intermediate Algebra for College Students (7th Edition)

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

Chapter 7 - Section 7.4 - Adding, Subtracting, and Dividing Radical Expressions - Exercise Set - Page 541: 110

Answer

$\frac{3x^2+8x+6}{(x+2)(x+3)^2}$.

Work Step by Step

The given expression is $=\frac{2}{x^2+5x+6}+\frac{3x}{x^2+6x+9}$ Factor $x^2+5x+6$. Rewrite the middle term $5x$ as $3x+2x$. $\Rightarrow x^2+3x+2x+6$ Group the terms. $\Rightarrow (x^2+3x)+(2x+6)$ Factor each group. $\Rightarrow x(x+3)+2(x+3)$ Factor out $(x+3)$. $\Rightarrow (x+3)(x+2)$ Factor $x^2+6x+9$. Rewrite the middle term $6x$ as $3x+3x$. $\Rightarrow x^2+3x+3x+9$ Group the terms. $\Rightarrow (x^2+3x)+(3x+9)$ Factor each group. $\Rightarrow x(x+3)+3(x+3)$ Factor out $(x+3)$. $\Rightarrow (x+3)(x+3)$ Substitute back the factors into the given function. $=\frac{2}{(x+3)(x+2)}+\frac{3x}{(x+3)(x+3)}$ The LCD is $(x+2)(x+3)(x+3)$. $=\frac{2(x+3)}{(x+2)(x+3)(x+3)}+\frac{3x(x+2)}{(x+2)(x+3)(x+3)}$ Use the distributive property. $=\frac{2x+6}{(x+2)(x+3)(x+3)}+\frac{3x^2+6x}{(x+2)(x+3)(x+3)}$ Add numerators because denominators are the same. $=\frac{2x+6+3x^2+6x}{(x+2)(x+3)(x+3)}$ Simplify. $=\frac{3x^2+8x+6}{(x+2)(x+3)(x+3)}$ $=\frac{3x^2+8x+6}{(x+2)(x+3)^2}$.
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