Answer
$-2b^{2}\sqrt[5] {2}$
Work Step by Step
Step 1: $\sqrt[5] {-64b^{10}}$
Step 2: $\sqrt[5] {-64}\times \sqrt[5] {b^{10}}$
Step 3: $\sqrt[5] {-32\times 2}\times \sqrt[5] {b^{10}}$
Step 4: $\sqrt[5] {(-2)^{5}}\times \sqrt[5] {2}\times (b^{10})^{\frac{1}{5}}$
Step 5: $-2\times \sqrt[5] {2}\times b^{2}$
Step 6: $-2\times b^{2} \times\sqrt[5] {2}$
Step 7: $-2b^{2} \times\sqrt[5] {2}$
Step 8: $-2b^{2}\sqrt[5] {2}$