Answer
The error is in the first step, turning $\frac{\sqrt[3] 64}{\sqrt 64}$ into $\sqrt[3] \frac{64}{64}$.
Work Step by Step
Because we are taking the square root of 64 in the denominator of the first fraction and the cube root of the 64 in the numerator, the numerator and denominator cannot be combined under a single radical.
