the cost the company is getting for moving about the sugar is, first off the rental of the trucks, the rental company is charging a "service fee" of 2500.
Now, that's a fixed unit, like when a cable company charges you for a cable setup fee, a quick fee just to get things rolling, usually for paperwork and other processing needed to get the client account going.
then they decided to charge not for mileage but for tonnage, so, the charge isĀ 100 bucks for each ton of sugar moved by the rented trucks.
so, if the trucks move "x" tons of sugar, then the charge is 100 * x, or 100x.
so the cost C is the fixed processing fee of 2500, plus the tonnage charge, of 100x.
C(s) = 2500 + 100x.
now, is a linear equation, so, to graph a line, all you need is two points, pick any random tonnage, say hmm "x = 2" and say you get a C(x) of 2500 + 100(2) which is 2700
since "x" is the independent variable, use the well, you guessed it, the x-axis for it, and C(x) will use the y-axis, pick another random "x" ton value to get a C(x), and graph it away.