Răspuns :
a+b+c=220
c-(a+b)=44
c=44+a+b
(b+c)-a=102
a=b+c-102
a=b+44+a+b-102
0=2b -58
2b=58
b=29
c-(a+29)=44
c-a=44-29
c=a+15
a+29+a+15=220
2a+44=220
2a=220-44
2a=176
a=88
c=88+15=103
c-(a+b)=44
c=44+a+b
(b+c)-a=102
a=b+c-102
a=b+44+a+b-102
0=2b -58
2b=58
b=29
c-(a+29)=44
c-a=44-29
c=a+15
a+29+a+15=220
2a+44=220
2a=220-44
2a=176
a=88
c=88+15=103
a + b + c = 220
(a + b) - c = 44
(b + c) - a = 102
a + b - c = 44
- a + b + c = 102 scadem aceste 2 ecuatii
_______________________
/ 2b / = 146
b = 73
a + 73 - c = 44
a = c - 29, inlocuim pe a in prima ecuatie
c - 29 + 73 + c = 220
2c = 220 + 29 - 73
2c = 176
c = 88
a + 73 + 88 = 220
a = 220 - 73 - 88
a = 59
(a + b) - c = 44
(b + c) - a = 102
a + b - c = 44
- a + b + c = 102 scadem aceste 2 ecuatii
_______________________
/ 2b / = 146
b = 73
a + 73 - c = 44
a = c - 29, inlocuim pe a in prima ecuatie
c - 29 + 73 + c = 220
2c = 220 + 29 - 73
2c = 176
c = 88
a + 73 + 88 = 220
a = 220 - 73 - 88
a = 59