A farmer is building a rectangular pen for some goats. She needs to have 3500 square feet of land fenced in for the pen. The material she will be using for the fencing costs $5 per foot for the front of the pen and $3 per foot for the other three sides of the pen. The farmer would like to minimize the cost of the fence. Use the variables r for width and the y for length. (a) (3 points) Determine the equation of the constraint/restriction for this question: Constraint/Restriction: (b) (5 points) Determine the equation of the function to be minimized, the objective function. Give your equation in terms of a SINGLE variable. Function to be Minimized: