why is this question so difficult?

The height of a rocket launched from the ground is given by the function s(t) = -16 t^2 + 80 t,
where s is in feet above ground and t is in seconds.

After 3 seconds, the rocket is ________ feet above ground.

Question

why is this question so difficult?

The height of a rocket launched from the ground is given by the function s(t) = -16 t^2 + 80 t,
where s is in feet above ground and t is in seconds.

After 3 seconds, the rocket is ________ feet above ground.

anonymous · Answer

then After 3 seconds, the rocket is traveling at a velocity of _________ feet per second.

lgbasallote · Answer

Can I just answer your first question?

Because it is..lol xD

anonymous · Answer

lol sure!!

anonymous · Answer

s(3)=-16(3)^2+80(3)=96 ft

anonymous · Answer

v(t)=s'(t)=-32t+80
v(3)=-32(3)+80=-16ft/s

anonymous · Answer

thanks

anonymous · Answer

wait how do I find if The rocket is 60 feet above ground at what times?

anonymous · Answer

set s(t)=60,solve for t

anonymous · Answer

you'll have a quadratic equation, it's a parabola so  there should be 2 answers

anonymous · Answer

ok i got -38,200

anonymous · Answer

and the the other answer is pos. 38,200

anonymous · Answer

am I right?

anonymous · Answer

am I right?

anonymous · Answer

let me check

anonymous · Answer

i highly doubt those are the right answers, the rocket will have hit the ground long before those times

anonymous · Answer

$$-16t^2+80x-60=0$$
Solving for t, 
$$t= \frac{(5 \pm \sqrt{10})}{2}$$