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: 105

Answer

$2\sqrt2$.

Work Step by Step

Let the irrational number be $a$. We can write. $\Rightarrow a-(2\sqrt{18}-\sqrt{50})=\sqrt2$ Factor the radicands using the greatest perfect square factors inside the parentheses. $\Rightarrow a-(2\sqrt{2\cdot 3^2}-\sqrt{2\cdot 5^2})=\sqrt2$ Simplify. $\Rightarrow a-(2\cdot 3\sqrt{2}-5\sqrt{2})=\sqrt2$ $\Rightarrow a-(6\sqrt{2}-5\sqrt{2})=\sqrt2$ Apply the distributive property. $\Rightarrow a-(6-5)\sqrt{2}=\sqrt2$ Simplify. $\Rightarrow a-(1)\sqrt{2}=\sqrt2$ Clear the parentheses. $\Rightarrow a-\sqrt{2}=\sqrt2$ Add $\sqrt 2$ to both sides. $\Rightarrow a-\sqrt{2}+\sqrt{2}=\sqrt2+\sqrt{2}$ Simplify. $\Rightarrow a=2\sqrt2$ Hence, the number is $2\sqrt2$.
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