Physics
posted by Eddy .
Two balls have masses 44 kg and 86 kg. The 44 kg ball has an initial velocity of 80 m/s (to the right) along a line joining the two balls and the 86 kg ball is at rest. The 86 kg ball has initial velocity of −24 m/s. The two balls make a headon elastic collision with each other.
(1)What is the final velocity of the 44 kg ball?
(2)The final velocity of the 86Kg ball?
Answer in units of m/s

you have to use both conservation of momentum and energy.
Start with conservation of momentum, solve for one of the ball's velocity in terms of all the other variables, then substitute that into the conservation of energy.
The algebra is substantial, so be prepared.