1. Make an equation.
Moving company #1: y = 17x + 840
Moving company #2: y = 22x + 760
2. Put the equations together and solve
17x + 840 = 22x + 760
-17x -17x
840 = 5x + 760
-760 -760
80 = 5x
5 5
16 = x
When a job is 16 hours they both charge the same thing.