111,11:(21.45-1.9x) - 3.2=51

111,11:(21.45-1.9x) - 3.2=51

111,11:(21.45-1.9x) =51+3,2

111,11:(21.45-1.9x) =54,2

111,11:54,2=21,45-1,9х

2,05=21,45-1,9х

1,9х=21,45-2,05

1,9х=19,4

х=19,4:1,9

х=194/19=10 4/19=10,21

111,11/(21,45-1,9x)=51+3.2

111.11/(21.45-1.9x)=54.2

54.2*(21.45-1.9x)=111.11

1162.59-102.98x=111.11

-102.98x=111.11-1162.59

-102.98x=-1051.48

102.98x=1051.48

x=1051.48/102.98

x=105148/10298

x=52574/5149

Избираем лучшее решение!