Question 897059
We have two data points, (15, 430) and (25, 610)
now we can calculate the slope of the line 
m = (610 - 430) / (25 - 15) = 180 / 10 = 18
so far we have
C(x) = 18x +b
we can use one of the points to calculate b
430 = 18*15 + b
b = 430 - 270 = 160
therefore, our cost equation is
C(x) = 18x +160