Chapter 5: Problem 15
Use the distributive property to help simplify each of the following. \(\frac{3 \sqrt{18}}{5}-\frac{5 \sqrt{72}}{6}+\frac{3 \sqrt{98}}{4}\)
Short Answer
Expert verified
The simplified expression is \( \frac{373\sqrt{2}}{60} \).
Step by step solution
01
Express Square Roots in Simplest Form
First, simplify each square root expression: - For \( \sqrt{18} \), notice that \( 18 = 9 \times 2 \). Thus, \( \sqrt{18} = \sqrt{9 \times 2} = \sqrt{9} \times \sqrt{2} = 3\sqrt{2} \).- For \( \sqrt{72} \), notice that \( 72 = 36 \times 2 \). Thus, \( \sqrt{72} = \sqrt{36 \times 2} = \sqrt{36} \times \sqrt{2} = 6\sqrt{2} \).- For \( \sqrt{98} \), notice that \( 98 = 49 \times 2 \). Thus, \( \sqrt{98} = \sqrt{49 \times 2} = \sqrt{49} \times \sqrt{2} = 7\sqrt{2} \).
02
Substitute Simplified Expressions
Substitute the simplified forms into the initial expression:\[ \frac{3 \sqrt{18}}{5} - \frac{5 \sqrt{72}}{6} + \frac{3 \sqrt{98}}{4} \] becomes:\[ \frac{3 \times 3\sqrt{2}}{5} - \frac{5 \times 6\sqrt{2}}{6} + \frac{3 \times 7\sqrt{2}}{4} \].
03
Simplify Each Term
Compute the coefficients for each term:- For the first term \( \frac{3 \times 3\sqrt{2}}{5} \), this simplifies to \( \frac{9\sqrt{2}}{5} \).- For the second term \( \frac{5 \times 6\sqrt{2}}{6} \), cancel out the factor of 6, simplifying to \( 5\sqrt{2} \).- For the third term \( \frac{3 \times 7\sqrt{2}}{4} \), this simplifies to \( \frac{21\sqrt{2}}{4} \).
04
Make Denominators Common
To simplify the expression further, find a common denominator, which is 60 for denominators 5, 6, and 4.- Multiply \( \frac{9\sqrt{2}}{5} \) by \( \frac{12}{12} \) resulting in \( \frac{108\sqrt{2}}{60} \).- Multiply \( 5\sqrt{2} \) by \( \frac{10}{10} \) resulting in \( \frac{50\sqrt{2}}{60} \).- Multiply \( \frac{21\sqrt{2}}{4} \) by \( \frac{15}{15} \) resulting in \( \frac{315\sqrt{2}}{60} \).
05
Combine the Expressions
Combine all the terms into a single expression by adding the numerators:\[ \frac{108\sqrt{2}}{60} - \frac{50\sqrt{2}}{60} + \frac{315\sqrt{2}}{60} = \frac{(108 - 50 + 315)\sqrt{2}}{60} \].
06
Simplify the Result
Calculate the final expression: Add up the numerators: \[ 108 - 50 + 315 = 373 \].So the expression becomes: \[ \frac{373\sqrt{2}}{60} \].This is already in its simplest form.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Simplifying Square Roots
Simplifying square roots means finding a simpler or more convenient form of square root expressions. Often, numbers under a square root (\(\sqrt{}\)) can be broken into smaller factors. If a factor is a perfect square, it can be extracted from the square root.
- For example, consider \(\sqrt{18}\). Instead of calculating the square root directly, notice that 18 is made up of \(9 \times 2\).
- Since \(\sqrt{9}\) is 3, we can rewrite \(\sqrt{18}\) as \(3\sqrt{2}\).
- 72 can be factored to \(36 \times 2\), and since \(\sqrt{36}\) is 6, \(\sqrt{72}\) simplifies to \(6\sqrt{2}\).
- Similarly, \(98 = 49 \times 2\) simplifies to \(7\sqrt{2}\) because \(\sqrt{49}\) is 7.
Simplifying Algebraic Expressions
An algebraic expression like \(\frac{3 \times 3\sqrt{2}}{5}\) includes variables, coefficients, and sometimes roots. Simplifying these expressions involves a few important steps.
Start by carrying out operations within the numerator and the denominator separately:
Start by carrying out operations within the numerator and the denominator separately:
- The expression \(3 \times 3\sqrt{2}\) simplifies to \(9\sqrt{2}\).
- Place the result over the existing denominator, in this case, 5.
- The original task had the expression broken down into smaller, simpler parts before dealing with it as a whole.
Common Denominators in Fractions
Combining fractions involves making the denominators match. This is essential when you add or subtract fractions. If the denominators are different, planning is needed to find a common denominator, which is typically the lowest common multiple (LCM) of the denominators.
- For example, working with denominators 5, 6, and 4, the LCM is 60.
- Change each fraction like \(\frac{9\sqrt{2}}{5}\) by multiplying the numerator and the denominator by the necessary amount—\(\frac{12}{12}\) in this case—to get a new denominator of 60.
- Sum or subtract the adjusted numerators and place the result over the common denominator.