Răspuns :
4c+6a=440
a= c+15
4c+ 6x(c+15)=440
4c+ 6c+ 90=440
10c=440-90
10c=350
c=350:10
c=35pe a il afli inlocuindu-l in relatia de mai sus
4c+6a=440
a= c+15
4c+ 6x(c+15)=440
4c+ 6c+ 90=440
10c=440-90
10c=350
c=350:10
c=35pe a il afli inlocuindu-l in relatia de mai sus