84. Launching a Rock Larry uses a slingshot to launch a rock straight up from a point 6 ft above level ground with an initial velocity of 170ft/sec.
(a) Find an equation that models the height of the rock t seconds after it is launched and graph the equation. (See Example 8 in Section 2.1.)
(b) What is the maximum height of the rock? When will it reach that height?
(c) When will the rock hit the ground?