The path of a clay disk can be represented with the parabolic h(t)=-4.9t^2+32t+2

How much time has passed when the disc is at a height of 20 meters
h(t) is the height in meters after t seconds

Question

The path of a clay disk can be represented with the parabolic h(t)=-4.9t^2+32t+2

How much time has passed when the disc is at a height  of 20 meters
h(t) is the height in meters after t seconds

anonymous · Answer

Because a <0, this parabola opens downward. 
I believe you need to set it up as 20 = -4.9t^2 + 32t + 2
then subtract 20 from both sides and solve it from there.

anonymous · Answer

Do I need to put it into vertex form to solve for Y?

anonymous · Answer

Don't think so. You'll be solving for t in -4.9t^2 + 32t - 18 = 0. Now you can use the quad formula.