Find the midpoint of the parabola with:
(That will give you the time at which it should explode.)
And to find the height simply plug that time in for t and it will give you a maximum.
Fireworks are launched into the air. The quadratic function
s(t)=-4t^2+50t+1
models the fireworks' height, s(t) in metres, t seconds after they are launched.
a) when should the fireworks explode so that they go off at the greatest height?
b) what is that height?