Solve for A as a function of x.

Question

Suppose $A(x)=x^2+\frac{4V}{x}$ where A is the surface area and V is a fixed volume. If $x=2^\frac{1}{3}\cdot V^\frac{1}{3}$ At this point I rewrote the formula for A with a common denominator $A=\frac{x^3+4V}{x}$ And then substituting for x I get $A=\frac{(2^\frac{1}{3}\cdot V^\frac{1}{3})^3+4V}{2^\frac{1}{3}\cdot V^\frac{1}{3}}$ simplifying I get $\frac{6V}{2^\frac{1}{3}\cdot V^\frac{1}{3}}$ Now can this last expression not be written as one product $2^1\cdot 3^1\cdot V^1\cdot 2^\frac{-1}{3}\cdot V^\frac{-1}{3}$ And so $A=3\cdot 2^\frac{2}{3}\cdot V^\frac{2}{3}$ The answer is $A=3\cdot 2^\frac{1}{3}\cdot V^\frac{2}{3}$ I'm having trouble where I've made the error with the fractional powers.