Answer
$x=15$
Work Step by Step
$j(x)=-\frac{4}{5}x+7$
Substitute $-5$ for $j(x)$ to get
$-5=-\frac{4}{5}x+7$
Subtract $7$ from both sides of the equation.
Then, we have
$-5-7=-\frac{4}{5}x+7-7$
Or $-12=-\frac{4}{5}x$
Multiply by $-\frac{5}{4}$ on both sides to obtain
$-12(-\frac{5}{4})=-\frac{4}{5}x(-\frac{5}{4})$
$\implies 15=x$
When $x=15$, $j(x)=-5$
