1. Max z = 20x + 12y ST: Machine const (hours) 2x + 3y 120 Assembly const (hours) 4x + 1y 80 x, y 0 Change the objective function to the following. What are the slopes of the following objective functions? Determine the solution graphically or with the number line before solving on the computer. Solve in R and report the results (remember to include the value of z with the solution). a. z = 20x + 4y b. z = 5x +15y c. z = 3x + 1y