math
posted by colin .
The height, h(t), of a projectile, in metres, can be modelled by the equation
h(t) = 14t – 5t2, where t is the time in seconds after the projectile is released. Can the projectile ever reach a height of 9m? Explain.

h(t) = t(145t)
max height is achieved at t = 7/5
h(7/5) = 9.8
so, yes.