# How do you solve abs(6-b)= -1?

$\left\mid \text{anything} \right\mid \ge 0$ (by definition of absolute value)
Since $\left\mid 6 - b \right\mid \ge 0$
$\textcolor{w h i t e}{\text{XXXXXXXXXXX}} \left\mid 6 - b \right\mid \ne - 1$