Răspuns :
a+b+c=70
a=b+6
b+c=42
----------------
a+b+c=70
a+42=70n /-42
a=28
b=28-6
b=22
c=42-b
c=42-22
c=20
a=b+6
b+c=42
----------------
a+b+c=70
a+42=70n /-42
a=28
b=28-6
b=22
c=42-b
c=42-22
c=20
a+b+c=70
a=6+b
b+c=42
a+42=70
a=70-42
a=28
28=6+b
28-6=b
22=b
22+c=42
c=42-22
c=20
V:28+22+20=70
a=6+b
b+c=42
a+42=70
a=70-42
a=28
28=6+b
28-6=b
22=b
22+c=42
c=42-22
c=20
V:28+22+20=70