## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$x=-4~or~x=4$.
Using the definition of the absolute value, we have $$|-2x|=8\Longrightarrow -2x=8~or~ -2x=-8 .$$ Thus, we solve the two possible equations: $-2x=8$ or $-2x=-8$ $x=-4~or~x=4$.