x, y -numerele
x+y=s
x-y=d
d+340=s
s:d=4 rest 40 ⇒4d+40=s
d+340=4d+40
300=3d
d=100
100+340=s
s=440
Am aflat suma(s) si diferenta(d), acum aflam numerele x, y
x+y=440
x-y=100
---------------(adunam cele doua relatii)
2x=540
x=270
y=440-270
y=170
verificare (270+170):(270-170)=440:100=4 rest 40
Numerele sunt 270 si 170.