38iaurt+14smantana=132 lei
36iaurt+7smantana=100lei
dublam al doilea rand
(36iaurt*2)+(7smantana*2)=2*100lei
72iaurt+14smantana=200lei
coboram
36iaurt+7smantana=100lei
facem diferenta
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(72-36iaurt)+(7-7smantana)=200-100lei
36iaurt=100lei
1iaurt=100:36(in lei)
inlocuim
100:36*36iaurt+7smantana=100lei