#### Answer

$9\sqrt[3] 2$

#### Work Step by Step

$\sqrt[3] {128}+\sqrt[3] {250}$
=$\sqrt[3] {64\times2}+\sqrt[3] {125\times2}$
=$(\sqrt[3] {64} \times \sqrt[3] 2)+(\sqrt[3] {125} \times \sqrt[3] 2)$
=$(\sqrt[3] {4^{3}} \times \sqrt[3] 2)+(\sqrt[3] {5^{3}} \times \sqrt[3] 2)$
=$(4\times \sqrt[3] 2)+(5\times \sqrt[3] 2)$
=$4\sqrt[3] 2+5\sqrt[3] 2$
=$9\sqrt[3] 2$