Răspuns :
X + Y = 148
X + X- 18 =148
2X=148+18
2X=166
X=83
Y=83-18=65
Verificare 83+65=148
X + X- 18 =148
2X=148+18
2X=166
X=83
Y=83-18=65
Verificare 83+65=148