a-pret o lalea
b-pret o frezie
4a+3b=75 (ron) |×2
5a+6b=114 (ron)
8a+6b=150 (ron)
5a+6b=114 (ron)
------------------------ (-) scadem
3a+ \ =36
3a=36 => a=12
4a+3b=75 => 3b=75-4a => b=(75-4a)/3
b=(75-4×12)/3
b=(75-48)/3
b=27/3=9
deci o lalea costa 12 lei iar o frezie 9 lei
verificare
4×12+3×9=75
5×12+6×9=114