You will have to multiply both the numerator and the denominator by sums of cubes.
Sums of Cubes: $a^3+b^3=(a+b)(a^2-ab+b^2)$
So to get $\sqrt[3]{x}+2$ into a perfect number with no radicals, you have to multiply it by $\sqrt[3]{x^2}-2\sqrt[3]{x}+\sqrt[3]{64}$. Doing so to the numerator and denominator gives us $$\boxed{\frac {\sqrt[3]{x^2}-2\sqrt[3]{x}+4}{x+8}}$$