I need help with this formular please 0.5mu^2+0.5mu^2=0.5mv^2+0.5mv^2 I will like to know if it's for elastic or inelastic collision please

Hint: kineticenergy is conserved in an elastic collision. In an inelastic collision some (or all) of the KE is converted to heat, so the KE of the system after the collision is less than it was before.