Выразите из формулы !!!!!!!!m4!!!!!!! L*m1+c1*m1*(t3-t2)=c2*m2*(t3-t1)+c3*m3*(t3-t1)+L*(m1-m4) 

L*m1+c1*m1*(t3-t2)=c2*m2*(t3-t1)+c3*m3*(t3-t1)+L*(m1-m4)  L*m1+c1*m1*(t3-t2)-c2*m2*(t3-t1)-c3*m3*(t3-t1)=L*(m1-m4)  (m1-m4)=(L*m1+c1*m1*(t3-t2)-c2*m2*(t3-t1)-c3*m3*(t3-t1)) /L -m4=-m1+ (L*m1+c1*m1*(t3-t2)-c2*m2*(t3-t1)-c3*m3*(t3-t1))/L m4=m1- (L*m1+c1*m1*(t3-t2)-c2*m2*(t3-t1)-c3*m3*(t3-t1))/L=   =(L*m1-L*m1-c1*m1*(t3-t2)+(c2*m2*+c3*m3*)(t3-t1))/L= =((c2*m2*+c3*m3*)(t3-t1)-c1*m1*(t3-t2))/L