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Ch. P - Fundamental Concepts of Algebra
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 1, Problem 47

Rationalize the denominator.
25\(\frac{\sqrt{2}\)}{\(\sqrt{5}\)}

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1
Identify the expression to rationalize: \(\frac{\sqrt{2}}{\sqrt{5}}\). The goal is to eliminate the square root from the denominator.
Multiply both the numerator and the denominator by \(\sqrt{5}\), which is the conjugate in this case, to rationalize the denominator. This gives: \(\frac{\sqrt{2}}{\sqrt{5}} \times \frac{\sqrt{5}}{\sqrt{5}}\).
Use the property of square roots that \(\sqrt{a} \times \sqrt{a} = a\) to simplify the denominator: \(\sqrt{5} \times \sqrt{5} = 5\).
Multiply the numerators together: \(\sqrt{2} \times \sqrt{5} = \sqrt{2 \times 5} = \sqrt{10}\).
Write the new expression with the rationalized denominator: \(\frac{\sqrt{10}}{5}\). This is the simplified form with no radical in the denominator.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Rationalizing the Denominator

Rationalizing the denominator involves eliminating any radicals (square roots) from the denominator of a fraction. This is done by multiplying the numerator and denominator by a suitable expression that will remove the radical from the denominator, making the expression easier to interpret and use.
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Properties of Square Roots

Square roots have properties such as \( \sqrt{a} \times \sqrt{b} = \sqrt{ab} \) and \( \frac{\sqrt{a}}{\sqrt{b}} = \sqrt{\frac{a}{b}} \). Understanding these properties helps simplify expressions involving radicals and is essential when rationalizing denominators.
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Multiplying by a Form of One

To rationalize a denominator, multiply the fraction by a form of one that contains the radical in the denominator, such as \( \frac{\sqrt{5}}{\sqrt{5}} \). This does not change the value of the expression but helps eliminate the radical from the denominator.
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