Arocket is fired upward from some initial distance above the ground. its height in feet, h, above the ground, t seconds after it is fired, is given by h=−16t^2+96t+2560.

what is the rocket's maximum height?

how long does it take for the rocket to reach its max height?

after it's fired, the rocket reaches the ground at t=__ sec.

Check the picture below.



so.. the maximum point is at   

and it happened after   

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now, when the rocket reaches the ground, as you saw on the picture, y = 0, thus



"t" is an amount in seconds, for this specific phenomena, it cannot be negative, so -10 is not a feasible value.