Chapter 7 - Exponents and Exponential Functions - 7-5 Rational Exponents and Radicals - Practice and Problem-Solving Exercises - Page 451: 45

$2b^{\frac{5}{3}}-4a^{\frac{3}{4}}$

We are given: $(\sqrt[3] 8b^5) - (4\sqrt[4] 256a^3)$ $=(\sqrt[3] (8b)^3.b^2) - (4\sqrt[4] 256a^3)$ $=2b\sqrt[3] b^2 - 4\sqrt[4] a^3$ $=2b^3b^{\frac{2}{3}}-4a^{\frac{3}{4}}$ $=2b^{\frac{5}{3}}-4a^{\frac{3}{4}}$