-x - 9

You want to get x by itself.
First subtract 9 from both sides of the equation.
-x - 9

+9 +9
-x

Then divide -1 on both sides.
-x/-1

I'm pretty sure when you divide a negative number when solving inequalities, you switch the sign.
x
A negative times a negative is a positive so...
( - ) ( - ) ( - ) ( -10x ) = -5
10x = -5
x = -5/10
x = -1/2
The original price would be $58.75