For this problem we need to define the variable first:
Define: x represent the number of hours used for the task
Equation:

Solve: Now we just need to solve for x. If we subtract 14x in both sides of the equation we got:

And now if we divide both sides by 8 we got:

So then finally the answer is: At 32 or more hours Tim's Painting would be a better deal since it would cost less