13. (4 points) The following is a graph of y = f(x). -28 24 20 16 -12- -8- -4- -2 -1 0 1 2 3 4 .-4- -8 -12 -16 Use the graph to evaluate f(x) dx. 14. (4 points) Evaluate the following definite integral using the Fundamental Theorem of Calculus: dx