I just need the answer to this one.

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

How can you tell when x and y are not directly proportional?

How can you find the mean absolute deviation (mad) for this set of data?