Răspuns :
salut!
a,b-nr. cautate
a+b=120
b=a-20=>a=b+20
_______
a,b=?
_______
b+20+b=120
2b=120-20
2b=100
b=100:2
b=50
a=50+20
a=70
a,b-nr. cautate
a+b=120
b=a-20=>a=b+20
_______
a,b=?
_______
b+20+b=120
2b=120-20
2b=100
b=100:2
b=50
a=50+20
a=70