## Finding amount of Speed needed

Hi
I am working on an application which has a Cannon fiering a Projectile at an Angle and at a Speed, above Ground Level.

I have 4 formular wich calculates nessesary data for the Projectile, before the Projectile starts moving:

...
Filnal Y Velocity
Code:
Sqr( ( Sin( ( "Projectile Anlge" )*( "Projectile Speed" ) )^2 ) - 2 * "Gravity" * "DeltaY"
Total Flight Time
Code:
 ( "Filnal Y Velocity" + "Initial Y Velocity" ) / "Gravity"
Natural Travel Distance X ( Acounting for only Speed and Angle )
Code:
 Cos( "Projectile Anlge" ) * "Projectile Speed" * "Flight Time"
Wind Travel Distance X ( Acounting only for Wind Power )
Code:
 ( ( "Flight Time" *( "Flight Time" + 1 ) )/2.0) * "Wind Power"
...
I then use these 4 formulas to predict the exact impact point of the Projectile along the Ground Level, like this
Code:
Impact Point X = "Start Possition X" + "Natural Travel Distance X" + "Wind Travel Distance X"
...
How would i be able to "rearange" this formula so that
instead of it returning the Impact Point along the Ground Level ( based on Angle, Speed, Gravity, Wind Power )
It will return the amount of "Speed" required to hit a specific point ( X ) along the Ground Level ( based on Angle, Gravity, Wind Power, Impact Point X )?

I realize this is not an easy question, but any help is appreciated