Answer
$\dfrac{b-2c}{a} \lt x \lt \dfrac{b+2c}{a}$
Work Step by Step
Consider the inequality $-2 \lt \dfrac{ax -b }{c}\lt 2$
This can also be written as: $-2c \lt ax-b \lt 2c$
or, $b-2c \lt ax \lt b+2c$
Our result is: $\dfrac{b-2c}{a} \lt x \lt \dfrac{b+2c}{a}$
