JAMB 2017 · UTME (set 2) · Q32

Simplify $\left(\sqrt[3]{64a^3}\right)^{-1}$ .

Worked solution (try it first)

Take the cube root of each part: $\sqrt[3]{64} = 4$ and $\sqrt[3]{a^3} = a$ , so $\sqrt[3]{64a^3} = 4a$ .
The index $-1$ means the reciprocal: $(4a)^{-1} = \frac{1}{4a}$ , option D.