а на 19.
42 : х = 6
х = 42 : 6
<u>х = 7</u>
42 : 7 = 6
47 - х = 19
х = 47 - 19
<u>х = 28</u>
47 - 28 = 19
6.4х-5.56х+3.84=10.14
6.4х-5.56х=10.14-3.84
0.84х=6.3
х=7.5