RĂSPUNS :)
15:5=3+18=21
39-21=18
a=18
V:18+15:5+18=39
SUCCES :)
a+15:5 = 39 - 18
a+15:5 = 21
a+15 = 5x21
a+15 = 105
a = 105 - 15
a = 90
metoda mersului invers
