The function h(t) = -5t2 + 20t + 25 represents the height (in meters) above the ground at time t (in seconds) of a stone thrown upwards at t = 0 from a cliff. (a) Write h(t) in vertex form, find the maximum height hmax the stone will reach and the time tmax at which this height will be reached. 21 seconce ? (b) Find the hight of the cliff, and the time when the stone hits the ground. (c) Using this information, plot the graph of h(t) in the (t, h) plane