Solving For Initial Velocity of a Projectile?

[Sandstorm]

I'm looking the formula(s) used for finding initial velocity of a projectile that starts at 5 meters above the ground, lands at 0 meters above the ground, in the time period of 5 seconds.

I know the numbers are aren't really useful when finding a formula, but they might help =).

Ask any clarifying questions, and I'll put the answers in the details section.

Thanks in advance!

[Jesse_J]

x(final)-x(initial) = v(initial)*t + 1/2*a*(t^2) where a = g

[Hawke]

y(t) = yinitial + Vyt -4.9t^2
0 = 5 meters + Vy(5 s) - 4.9(5 s)^2
Vy = -23.5 m/s