{7200-[100-999999:(11000-z)]x625}:225=7
7200-[100-999999:(11000-z)]x625= 7×225
7200-[100-999999:(11000-z)]x625= 1575
[100-999999:(11000-z)]x625 =7200- 1575
[100-999999:(11000-z)]x625 = 5625
100-999999:(11000-z) = 5625 : 625
100-999999:(11000-z) = 9
999 999 : (11 000 - z) = 100 - 9 = 91
11 000 - z = 999 999 : 91
11 000 - z = 10 989
z = 11 000 - 10 989
z = 11