Răspuns :
a+b+c=240
a-x=25
b-x=26
c-x=120
aduna primele 2 ecuatii si obtinem
a+b=25+26+2x
si inlocuim in prima ecuatie
25+26+x+c=240
x+c=240-25-26=189
c+x=189
c-x=120
aduna ecuatiile si obtinem
2c=309
c=309/2
a-x=25
b-x=26
c-x=120
aduna primele 2 ecuatii si obtinem
a+b=25+26+2x
si inlocuim in prima ecuatie
25+26+x+c=240
x+c=240-25-26=189
c+x=189
c-x=120
aduna ecuatiile si obtinem
2c=309
c=309/2
25+26+120=171, 240-171=69, 69/3=23, a=25+23=48, b =26+23=49, c=120+23=143, 48+49+143=240