19. Calculaţi: (a) [(7¹) 7] [7" (6° +36:6). c) [5 (18:45-11 (4:8); b) [(3-4":8 161:(2-24 dy [(7-2-87:4):3+11:19
~∆_∆ dau 50 punctr ∆_∆~​