Chapter 2 - Equations, Inequalities, and Problem Solving - Connecting: The Concepts - Exercises - Page 134: 9

$a\ge 0$

Using the properties of inequality, the solution to the given inequality, $ 10\ge-2(a-5) $, is \begin{array}{l}\require{cancel} 10\ge-2(a)-2(-5) \\\\ 10\ge-2a+10 \\\\ 10-10\ge-2a \\\\ 0\ge-2a \\\\ \dfrac{0}{-2}\le a \\\\ 0\le a \\\\ a\ge 0 .\end{array}