72 :8 x a =54
63 : 7 x a =63
54: 6 x a= 45


Răspuns :

72 : 8 x a = 54
9 x a = 54
a = 54 : 9
a = 6


63 : 7 x a = 63
9 x a = 63
a = 63 : 9
a = 7

54 : 6 x a = 45
9 x a = 45
a = 45 : 9
a = 5
72 : 8 • a = 54
9 • a = 54
a = 54 : 9
a = 6

63 : 7 • a = 63
9 • a = 63
a = 63 : 9
a = 7

54 : 6 • a = 45
9 • a = 45
a = 45 : 9
a = 5