Hey!
To solve this problem we'll divide both sides by -15. Doing this will get

on its own.
Original Equation :-15x = 240
New Equation {Changed by Dividing Both Sides by -15} :
=

Alright, now we simplify solve the equation.
Old Equation :
=
Solved {Old Equation Solved} :x = 16
Now we know that in the equation -15x = -240, x = 16.
Hope this helps!
- Lindsey Frazier ♥