h-39t-5t2 find the answer

Question

A model rocket is launched with an initial upward velocity of
39/ms
. The rocket's height
h
(in meters) after
t
seconds is given by the following.
=h−39t-5t2
Find all values of
t
for which the rocket's height is
22
meters.
Round your answer(s) to the nearest hundredth.
(If there is more than one answer, use the "or" button.)

Answer 1

22=39t-5t²

Set one side equal to 0.

0 = -5t² + 39t - 22

You can then use the quadratic formula to find the two possible solutions. If both of them are positive, then both are feasible.