Momentum (velocity), Math outbreak and simplification mostly

2 balls, both moving to the right - what are their velocity after collision?

Ball 1
M 60 kg
u0= 18 m/s

Ball 2
m=220 kg
v0= 7 m/s

Law on momentum conservation gives:
220*7+60*18=220*v+60*u (1)

As it is a elastic collision, it gives :
1/2(220)(7)^2+1/2(60)(18)^2=1/2(220)(v)^2+1/2(60)(u)^2 (2)

2620=220v*60u (1)

15110=1/2(220)(v)^2+1/2(60)(u)^2 (2)

v=(2620-60u)/220 (1)

input in equation (2)

I need to simplify equation (2) and put in (1), but I can't get further with that
Any help would be appreciated
Would be great if someone could double-check as well, not used with this.

Thanks in advance!

Once you put v into equation (2) as a function of u you have a quadratic equation in u. Solve it to get u and then plug it back into (1) to get v.

Note: the quadratic has two solutions. Check to make sure they make sense.

Ok, thank you.
Another question while I'm at it - if the collision was inelastic, how do you think then?
Can they get different velocity or does it have to be a "perfect" collision?
I'm intrested in a non-perfect collision if it is possible
I know the law of momentum before equals momentum after still is true.

For inelastic collision you need to know how much energy was lost to deformation. Momentum is always conserved.