notam: a suma Iuliei
b suma lui Danut
a+4000=b-4000
=> a+8000=b (1)
b+4000=3·(a-4000)
b+4000=3·a-12000
b=3·a-12000-4000
b=3·a-16000 (2)
Din (2)=(1)
=> 3·a-16000=a+8000
3·a-a=16000+8000
2·a=24000
a=24000:2
a=12000 lei;
(1)=> b=a+8000
b=12000+8000
b=20000
lei
R: Iulia are 12000 lei; Danut are 20000 lei
