Solve the following linear programming model by using the isocost line method: graph the constraints and identify the feasible region and determine the optimal solution (s) and its cost (show your work). Minimize cost = $1X + $2Y Subject to X + 3Y ≥ 90 8X + 2Y ≥ 160 3X + 2Y ≥ 120 Y ≤ 70 X, Y ≥ 0 

b. Are any constraints non-binding? If so, which one (s)?