Question 84295
h= -16t^2 + 16t + 3

You want to find t, but you know the height (7 feet) so just substitute that in.

7 = -16t^2 + 16t + 3

-16t^2 + 16t + 3 = 7 <-- Rewrote it to make it look nicer.

-16t^2 + 16t - 4 = 0

This is a quadratic equation. Try to solve it yourself but if you need more help, please write back.