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Ch. 4 - Inverse, Exponential, and Logarithmic Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 5, Problem 83

Solve each equation. See Examples 4–6. x2/3 = 4

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1
Start with the given equation: \(x^{2/3} = 4\).
To isolate \(x\), raise both sides of the equation to the reciprocal of the exponent \(\frac{2}{3}\), which is \(\frac{3}{2}\). This gives: \(\left(x^{2/3}\right)^{3/2} = 4^{3/2}\).
Simplify the left side using the power of a power property: \(x^{(2/3) \times (3/2)} = x^1 = x\).
Rewrite the right side \$4^{3/2}$ as \(\left(4^{1/2}\right)^3\), which means take the square root of 4 and then cube the result.
Calculate the right side step-by-step (square root of 4 is 2, then cube 2) to find the value of \(x\).

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Key Concepts

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

Rational Exponents

Rational exponents represent roots and powers simultaneously. For example, x^(2/3) means the cube root of x squared, or (x^2)^(1/3). Understanding how to manipulate and interpret these exponents is essential for solving equations involving fractional powers.
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Isolating the Variable

To solve equations, isolate the term containing the variable by performing inverse operations. In this case, you want to isolate x^(2/3) before applying further steps, which simplifies the process of solving for x.
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Solving Radical Equations

Equations with rational exponents often require rewriting the expression as a radical and then raising both sides to an appropriate power to eliminate the root. This step helps to solve for the variable and check for extraneous solutions.
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Solving Logarithmic Equations