Chapter 0: Problem 28
Simplify each expression. Assume that all variables are positive when they appear. $$\sqrt[3]{\frac{3 x y^{2}}{81 x^{4} y^{2}}}$$
Short Answer
Expert verified
\(\frac{1}{3x}\)
Step by step solution
01
- Simplify the fraction under the cube root
Simplify the fraction \(\frac{3 x y^{2}}{81 x^{4} y^{2}}\). Start by dividing the coefficients and then the variables. \(\frac{3}{81} = \frac{1}{27}\) and the variables \(\frac{x}{x^{4}}= \frac{1}{x^{3}}\). The \(y^{2}\) terms cancel each other: \(\frac{y^{2}}{y^{2}} = 1\). This gives us \(\frac{1}{27 x^{3}}\).
02
- Write the simplified expression under the cube root
Now the expression under the cube root is \(\frac{1}{27 x^{3}}\). So we need to simplify \(\root{3}{\frac{1}{27 x^{3}}}\).
03
- Apply the cube root to the numerator and the denominator
Apply the cube root separately to the numerator and the denominator: \(\root{3}{1}\) and \(\root{3}{27 x^{3}}\). \(\root{3}{1} = 1\) and \(\root{3}{27} = 3\). Also, since \(\root{3}{x^{3}} = x\), we have \(\root{3}{27 x^{3}} = 3x\).
04
- Write the final simplified expression
Combine the results of the cube root to get the simplified expression: \(\frac{1}{3x}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Simplifying Expressions
Simplifying expressions often means breaking down a complex expression into a more manageable and compact form. This makes it easier to work with and understand. For instance, knowing that the numerator and denominator in a fraction can sometimes be divided by the same number can be a powerful tool to simplify. Let's look at our example:
- The expression is \[ \sqrt[3]{\frac{3 x y^{2}}{81 x^{4} y^{2}}} \], and we aim to bring it to a simpler form.
- We start by simplifying the fraction under the cube root. Simplify the coefficients first, \[ \frac{3}{81} = \frac{1}{27} \].
- Next, simplify the variables. \[ \frac{x}{x^{4}} = \frac{1}{x^{3}} \], and \[ \frac{y^{2}}{y^{2}} = 1 \].
- Now, our fraction becomes \[ \frac{1}{27 x^{3}} \].
Variables
Variables are symbols used to represent numbers or values in expressions and equations. In our example, we have variables like x and y. Here's a breakdown:
- When simplifying expressions with variables, treat the variables just like numbers—divide them when they appear in both the numerator and the denominator.
- In \[ \frac{3 x y^{2}}{81 x^{4} y^{2}} \], we divided the x and y variables as follows:
- For the x variable: \[ x^{1} / x^{4} = x^{1-4} = x^{-3} = \frac{1}{x^{3}} \]
- For the y variable: \[ y^{2} / y^{2} = 1 \]
Fractions
Fractions represent parts of a whole and are expressed as \[ \frac{numerator}{denominator} \]. Simplifying fractions involves reducing them to their simplest form. In our example, we learned about this in a few ways:
- First, we divided the coefficients: \[ \frac{3}{81} \] which simplified to \[ \frac{1}{27} \].
- Next, we simplified the variables, yielding \[ \frac{x}{x^{4}} = \frac{1}{x^{3}} \].
- So our new simplified fraction was \[ \frac{1}{27 x^{3}} \].
- To further simplify, we applied the cube root to both the numerator and the denominator: \[ \sqrt[3]{1} = 1 \] and \[ \sqrt[3]{27 x^{3}} = 3x \].
- This gave our final simplified form: \[ \frac{1}{3x} \].