Fie x lei banii cheltuiti de Diana
y lei banii cheltuiti de Corina
z lei banii cheltuiti de Mara
x+y+z=214 x+y+z=214
z+26=x <=> z=x-26 <=>
y+18=x y=x-18
x+x-26+x-18=214 3x=214+44 x=258:3=86
z=x-26 <=> z=x-26 <=> z=86-26=60
y=x-18 y=x-18 y=86-18=68
Raspuns: Diana a cheltuit 86 lei
Mara a cheltuit 60 lei
Corina a cheltuit 68 lei