okay so the equation is -4.9t^2 - 39.2t + 1.6

Question

If the rockets explode at the highest point (which max height is 80 meters) One of the rockets is schedules to explode 2 minutes and 28 seconds into the program. When should the rocket be fired from the barge? (How long, from start of the program, before the rocket is fired)

plllllleaaassse hellp! thanks so much and godbless
4 minutes ago - 4 days left to answer.
Additional Details
so t is height of an object
and this equation = H(t)
31 seconds ago