Question

A ball is hit straight up in the air from a height of 4 ft. with an initial speed of 64 ft. per second.The height of the ball as a function of time can be modelled by the function h(t)=-16t2+64t+4.when will the ball reach a height of 52 ft.?

Answer 1

just solve

-16t2+64t+4 = 52
by the usual method(s). It might be easier to divide by -16 and rewrite it as
t^2-4t+3 = 0