In Exercises 1-2,
(a) use a graphing utility to graph the function,
(b) use the graph to approximate any x-intercepts of the graph,
(c)find any real zeros of the function algebraically, and
(d)compare the results of part(c) with those of part (b).
1. y = 4x3 − 20x2 + 25x
2. y = 4x3 + 4x2 − 8x - 8