у 7
---------------- = -------------
2,3 - 0,48 5,52
5,52у = 7 * (2,3 - 0,48)
5,52у = 7 * 1,82
5,52у = 12,74
у = 12,74 : 5,52
у = 1274/100 : 552/100
у = 1274/100 * 100/552
у = 1274/552
у = 2 170/552 = 2 85/276
--------------------------------------------------------------------
2,58 1,076 - 0,56
---------- = ---------------------
13 Z
2,58Z = 13 * (1,076 - 0,56)
2,58Z = 13 * 0,516
2,58Z = 6,708
Z = 6,708 : 2,58
Z = 2,6