Question

m1V1 + m2V2 = (m1+m2)V отсюда выразить m2

Answer 1

M1v1+m2v2=m1v+m2v
M2v2-m2v=m1v-m1v1
M2(v2-v)=m1(v-v1)
M2=m1(v-v1)/(v2-v)

Answer 2

m1V1 + m2V2 = (m1 + m2)V

Теперь выразим m2:

m2V2 = (m1 + m2)V - m1V1

m2 = ((m1 + m2)V - m1V1) / V2