Use your graphing utility to graph y = x⁴, y = x⁴ − x, y = x⁴ − 2x, and y = x⁴ − 3x on the same coordinate axes, using [−2, 2]1 by [−2, 5]1. What effect does the added term involving x have on the shape of the graph? Repeat using y = x⁴, y = x⁴ − x³, y = x⁴ − 2x³, and y = x⁴ − 3x³. Adjust the viewing rectangle appropriately.