Question 320622
Your graph will have points in the form (t,c).

STEPS:

1-select about 3 values for t (I chose t = 0...see below)

2-simplify the right side of the equation for each value selected in terms of t

3-When you find the value of t and c, plot each point (t,c) on the coordinate plane

4-Connect each point with a line

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Let's say that t = 0

c = 20t + 30

c = 20(0) + 30

c = 0 + 30

c = 30

Your first point to plot is (0,30).

Can you find two more points and then follow the above steps?

Your function is a straight line.  Can you do it now?