Question

Difficulty: EasyEquivalent Algebraic Expressions

For all positive values of xx, which of the following expressions is equivalent to (8x6)13(8x^6)^{\frac{1}{3}}?

  1. A
    2x32x^3
  2. B
    83x2\frac{8}{3}x^2
  3. 2x22x^2Answer
  4. D
    8x28x^2

Answer

The expression 2x22x^2
To find an equivalent expression, apply the exponent of 13\frac{1}{3} to each factor inside the parentheses. The expression (8x6)13(8x^6)^{\frac{1}{3}} becomes 813(x6)138^{\frac{1}{3}} \cdot (x^6)^{\frac{1}{3}}. Since 813=83=28^{\frac{1}{3}} = \sqrt[3]{8} = 2, and (x6)13=x613=x2(x^6)^{\frac{1}{3}} = x^{6 \cdot \frac{1}{3}} = x^2, the simplified expression is 2x22x^2.

Step-by-Step Solution

1
Apply the power of a product rule, (ab)n=anbn(ab)^n = a^n b^n, to distribute the exponent of 13\frac{1}{3} to both the coefficient and the variable term.
(8x6)13=813(x6)13(8x^6)^{\frac{1}{3}} = 8^{\frac{1}{3}} \cdot (x^6)^{\frac{1}{3}}
This separates the numerical coefficient and the variable part to simplify them individually.
2
Simplify the numerical coefficient by evaluating the cube root of 88.
813=28^{\frac{1}{3}} = 2
The exponent of 13\frac{1}{3} represents the cube root, and 23=82^3 = 8.
3
Simplify the variable term using the power of a power rule, (xa)b=xab(x^a)^b = x^{a \cdot b}.
(x6)13=x613=x2(x^6)^{\frac{1}{3}} = x^{6 \cdot \frac{1}{3}} = x^2
Multiplying the exponents simplifies the expression.
4
Multiply the simplified coefficient and variable term together.
2x22x^2
This gives the final simplified equivalent expression.

Key Concept

Simplifying algebraic expressions with fractional exponents using exponent rules.
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