a + c = 65
c + b = 52
a + b = 74
adunam ecuatiile
2a + 2b + 2c =191
a +b+ c = 191/2
b+c =52
scadem ecuatiile
a = 191/2-52 = 191/2-104/2=87/2
a+b+c= 191/2
a+b=74
scadem ecuatiile
c= 191/2-74=191/2-148/2=43/2
b+c=52
b=52-43/2=104/2-43/2=61/2
cel mai mare numar este a=87/2