Answer: So the ball hits the ground 4.06 secs after it's kicked.
Step-by-step explanation:h(t)= -16t^2 +64t +4
h(t)= -4( 4t^2 -16t -1) so a=4 b=-16 c=-1
Use Quadratic Formula: x=( -b+/- (b^2-4ac)^1/2)/ 2a
(16+/- ( 256-(4)(4)(-1))^1/2)/8= (16 +/- (272)^1/2)/8
x= (16+/-16.49)/8 ---->x=32.49/4= 4.062 sec
x=(16-16.49)/8 -----> x= -0.49/8= -0.06
So the ball hits the ground 4.06 secs after it's kicked.