1) Data
x: number of hours of repair
f(x) = cost
   x         f(x) = 15x
hours           $
   0           0
   1             15
   2             30
   3              45
   4              60
   5             75
    a             15a
2) Equation: y = 15x
3) Graph: it is a continuous straight line that starts at (0,0) and passes through all the points ordanized in the table.