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> Solve: $|3 - x| = x - 3$.
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> Answer: $|u| = -u$ when and only when $u \le 0$. So, $|3 - x| = x - 3$ when and only when $3 - x \le 0$; that is, $3 \le x$.
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Hi! I'm new here. I'm working out of this book called Schaum's Outlines 3,000 Solved Problems in Calculus. I understand that when solving for absolute values that you have to draw two equations, for example when solving for $|x+3|<5$ you must solve for both $x+3<5$ AND $x+3>-5$. But can someone please explain the process above to me? I don't understand it. Thanks!