Answer
$(4,\infty)$.
Work Step by Step
The equation according to the text: $x^3>4x^2\\x^3-4x^2>0\\x^2(x-4)>0$
The zeros: $x=0$ or $x-4=0\\x=4$.
Then, according to the table (where I used the zeros ($x=0,4$) to divide the number line into different parts), the solution set: $(4,\infty)$ because the function is positive in this interval.