In Problems 31–42, graph each polynomial function f by following Steps 1 through 5.

f (x) = x³ + x² − 12x

Steps for Graphing a Polynomial Function STEP 1: Determine the end behavior of the graph of the function. STEP 2: Find the x- and y-intercepts of the graph of the function. STEP 3: Determine the real zeros of the function and their multiplicity. Use this information to determine whether the graph crosses or touches the x-axis at each x-intercept. STEP 4: Determine the maximum number of turning points on the graph of the function. STEP 5: Use the information in Steps 1 through 4 to draw a complete graph of the function. To help establish the y-axis scale, find additional points on the graph on each side of any x-intercept.