Question

The function f(t)=-5t^2+15t+50 models the approximate height in feet of an object t seconds after it is launched. how many seconds does it take for the object to hit the ground?

Answer 1

f(t) can be factored to find the zeros.
.. f(t) = -5(t -5)(t +2) . . . . f(t) = 0 for t=-2, t=5

The object hits the ground after 5 seconds.