Question

Write $(5x)^3$ as a radical expression

Original question: Write (5x)3(5x)^3 as a radical expression.

(5x)3=53x35=125x35(5x)^3 = \sqrt[5]{5^3x^3} = \sqrt[5]{125x^3}

(2x)4/7=(2x)47=24x47=16x47(2x)^{4/7} = \sqrt[7]{(2x)^4} = \sqrt[7]{2^4x^4} = \sqrt[7]{16x^4}

Expert Verified Solution

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Key concept: A radical expression is usually used for fractional exponents. Since (5x)3(5x)^3 has a whole-number exponent, it is already in exponential form.

Step by step

The expression

(5x)3(5x)^3

already has an integer exponent, so it does not need to be rewritten as a radical expression.

If your teacher wants the most literal radical notation, you could write

(5x)31\sqrt[1]{(5x)^3}

but this is not standard because it does not simplify anything.

For comparison, a true radical conversion looks like

(5x)3/5=(5x)35(5x)^{3/5}=\sqrt[5]{(5x)^3}

Pitfall alert

Do not force an integer exponent into a radical form when the problem does not require it. Also, do not change (5x)3(5x)^3 into a fifth root unless the exponent is actually 3/53/5.

Try different conditions

If the intended expression were (5x)3/5(5x)^{3/5}, the radical form would be (5x)35\sqrt[5]{(5x)^3}. If it were (5x)4/7(5x)^{4/7}, it would be (5x)47\sqrt[7]{(5x)^4}.

Further reading

integer exponent, radical notation, rational exponent

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