Algebra 1: Common Core (15th Edition)

Published by Prentice Hall
ISBN 10: 0133281140
ISBN 13: 978-0-13328-114-9

Chapter 10 - Radical Expressions and Equations - 10-4 Solving Radical Equations - Practice and Problem-Solving Exercises - Page 637: 37

Answer

No solution.

Work Step by Step

The given equation is $\Rightarrow r=\sqrt{-6r-5}$ Square both sides. $\Rightarrow r^2=(\sqrt{-6r-5})^2$ Simplify. $\Rightarrow r^2=-6r-5$ Move all terms to the left hand side. $\Rightarrow r^2+6r+5=0$ Rewrite the middle term $6r$ as $5r+r$. $\Rightarrow r^2+5r+r+5=0$ Factor out common terms. $\Rightarrow r(r+5)+1(r+5)=0$ Factor out $(r+5)$. $\Rightarrow (r+5)(r+1)=0$ Use zero product property. $\Rightarrow r+5=0$ or $ r+1=0$ Solve for $r$. $\Rightarrow r=-5$ or $ r=-1$. Check $r=-5$. $\Rightarrow -5=\sqrt{-6(-5)-5}$ $\Rightarrow -5=\sqrt{30-5}$ $\Rightarrow -5=\sqrt{25}$ $\Rightarrow -5=5$ Not true. Check $r=-1$. $\Rightarrow -1=\sqrt{-6(-1)-5}$ $\Rightarrow -1=\sqrt{6-5}$ $\Rightarrow -1=\sqrt{1}$ $\Rightarrow -1=1$ Not true. Both the solutions are extraneous solutions. Hence, the equation has no solution.
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