Solving Momentum and Kinetic Energy Relations

[Garen]

Homework Statement

Homework Equations

[PLAIN]http://upload.wikimedia.org/math/7/7/4/7745116605c54295c6c3b696cea2d39f.png[/CENTER][/URL]

The Attempt at a Solution

I have gotten these problems wrong too many times. I know that I have to apply both the conservations of momentum and kinetic energy, but for some reason I can't come up with the right answer.

m1=21.3g v1=24.6cm/s
m2=11.6g v2=11.3cm/s

I don't know how to solve these relations with two unknowns. I've tried using substitution from the kinetic energy equation, but I still got it wrong for some reason. Any help for a desperate physics student?​

 

[Garen]

Anyone know where I'm going wrong?

 

[Garen]

No one? Really?

 

[Garen]

Maybe someone can refer me to another website to answer these questions?