Question

The cost T, in hundreds of dollars, of tuition and fees at many community colleges can be approximately by T=1/4c+6,where c is the number of credits for which a student registers. Graph the equation and use the graph to estimate the cost of tuition and fees when a student registers for a 4 two-credit courses.

Answer 1

To solve algebraically, a 4 two-credit courses has total of 4 x 2 = 8 credits. Substituting to the equation,
T = (1/4)c + 6
T = (1/4)(8) + 6
T = 2 + 6
T = 8
Since the units of T is in hundreds of dollars, the tuition is $800.

I'll leave the graphing to you since graph cannot be shown here. But just to give an idea how to graph, let c = x-coordinate and T = y-coordinate. Take 2 values of c and substitute it to the equation to get T. You have already have a point which we found above - point (8, 8).
For instance, c = 4.
T = (1/4)(4) + 6
T = 1 + 6
T = 7
thus another point on the line is (4, 7).

You have two points (8,8) and (4,7). Two points make a line so you can now draw the graph.

Hope this helps~ `u`