The total cost for a bakery to produce 100 gourmet cupcakes is $126, while the total cost to produce 120 gourmet cupcakes is $144. Let y represent the total cost for x gourmet cupcakes. Assume that a straight line can approximate the data.
(a) Find and interpret the slope of the cost line for the gourmet cupcakes.
(b) Determine an equation that models the data. Write the equation in the slope-intercept form.
(c) Use your answer from part (b) to determine an approximation of the cost of 180 gourmet cupcakes.