Question

15=7-|2x| Solve for x in this absolute value equation.

Answer 1

$15=7-|2x|\\ -|2x|=8\\ |2x|=-8\\ x\in\emptyset$

Answer 2

$7-|2x|=15\ \ \ \ |subtract\ 7\ from\ both\ sides\\\\-|2x|=8\\\\|2x|=-8-FALSE\\\\x\in\O\ because\ |a|\geq0\ for\ each\ a\in\mathbb{R}$