dau coreoana!!!!!!!!!!!!!

Răspuns:
..2a=3b= 7c=k
a=k/2
b=k/3
c= k/7
2b-a-c=1
2k/3-k/2-k/7=1
21k/42-14k/42/42=1
k=42
a= 21
b= 14
c=6