Answer
$\sqrt[3]{x^{2}}+\sqrt[3]{x}-20$
Work Step by Step
Use the FOIL method, along with
$\sqrt[n]{a}\times\sqrt[n]{b}=\sqrt[n]{ab},\qquad$
$\sqrt[n]{a^{n}}=(\sqrt[n]{a})^{n}=a$ (for positive a).
$F:\quad \sqrt[3]{x}\times\sqrt[3]{x}=\sqrt[3]{x^{2}}$
$O:\quad \sqrt[3]{x}\times 5=5\sqrt[3]{x}$
$I:\quad -4\times\sqrt[3]{x}=-4\sqrt[3]{x}$
$L:\quad -4\times 5=-20$
Add the terms (O and I are like terms...)
$...$= $\sqrt[3]{x^{2}}+\sqrt[3]{x}-20$
