The law of conservation of momentum proves Newton's law

Suppose the initial state of two objects: M1V1, M2V2, the state after interaction is: M1V12, M2V22, the interaction of these two objects is only affected by the internal force of the interaction, so momentum is conserved, that is, M1V1+M2V2= M1V12+M2V22. V12=V1+a1t, V22=V2+a2t, M1V1+M2V2=M1(V1+a1t)+M2(V2+a2t), simplified to: M1a1t+M2a2t=0 because the interaction time must be equal. that is, M1a1+M2a2=0, according to Newton's second law F=am: F1+F2=0, that is, F1=-F2, The motion state of our fake M0 object is: M0V0, after a period of time, the speed of M0, V1=V0+at, according to Newton's second law F=am, a=F/m, the object is not subject to external force, that is, F=0, a must be zero, that is, a=0, V1=V0. In particular, when V0=0, the object is at rest. Prove Newton's first law