A 2.0-kg ball is travelling east at 8.0 ~ Momentum

[Silverbolt]

A 2.0-kg ball is traveling east at 8.0 m/s when it has a perfectly elastic head-on collision with a 3.0-kg ball traveling west at 10.0 m/s. What are the final velocities of the two balls?

Please help I don't know where to start

 

[AATroop]

You know momentum is conserved when bodies collide, start with the momentum principle:
M1Vi + M2Vi = M1Vf + M2Vf

And try another formula, which represents the conservation of kinetic energy:

1/2(M1)(Vi)^2 + 1/2(M2)(Vi)^2 = 1/2(M1)(Vf)^2 + 1/2(M2)(Vf)^2