va rog ajutati-ma dau corona

○ 296+437+a = 854
733+a = 854
a = 854-733 = 121
○ 286+458+a = 789
744+a = 789
a = 789-744 = 45
○ 357+289-a = 289
646-a = 289
-646+a=-289
a = -289+646 = 357
○ 275+317+a = 999
592+a = 999
a = 999-592 = 407