Question

Rewrite the exponential expression as a radical expression.

Original question: Rewrite the exponential expression as a radical expression.

3x2/3-3x^{2/3}

Expert Verified Solution

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Key takeaway: To rewrite a fractional exponent as a radical, use the rule xm/n=xmnx^{m/n}=\sqrt[n]{x^m}. The coefficient stays outside the radical.

Use the fractional-exponent rule:

xm/n=xmnx^{m/n}=\sqrt[n]{x^m}

Here,

x2/3=x23x^{2/3}=\sqrt[3]{x^2}

So

3x2/3=3x23-3x^{2/3}=-3\sqrt[3]{x^2}

Answer: 3x23-3\sqrt[3]{x^2}


Pitfalls the pros know 👇 A common mistake is to put the negative sign inside the radical or to write a square root instead of a cube root. The denominator of the exponent tells you the index of the radical.

What if the problem changes? If the expression were 3x2/33x^{2/3}, the radical form would be 3x233\sqrt[3]{x^2}. If it were 3x1/2-3x^{1/2}, then it would become 3x-3\sqrt{x}.

Tags: fractional exponent, cube root, radical expression

FAQ

How do you rewrite -3x^{2/3} as a radical?

Use the rule x^(m/n) = n-th root of x^m. So x^(2/3) becomes the cube root of x^2, giving -3 times the cube root of x^2.

Does the negative sign go inside the radical?

No. The negative sign stays outside unless the original expression places it inside the base of the power.

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