Chapter 7 - Section 7.4 - Adding, Subtracting, and Multiplying Radical Expressions - Exercise Set - Page 438: 23

$-23\sqrt[3]{5}$

Using the properties of radicals, then, \begin{array}{l} -5\sqrt[3]{625}+\sqrt[3]{40} \\= -5\sqrt[3]{125\cdot5}+\sqrt[3]{8\cdot5} \\= -5\cdot5\sqrt[3]{5}+2\sqrt[3]{5} \\= -25\sqrt[3]{5}+2\sqrt[3]{5} \\= -23\sqrt[3]{5} .\end{array}