а)2,136/(1,9-x)=7,12
б)4,2*(0,8+у)=8,82

а) 7.12 ( 1.9-X)=2.136

13.528-7.12X=2.136

-7.12= -11.392

X=1.6

Б) 4.2 (0.8+y)=8.82

3.36+4.2y=8.82

4.2y=5.46

y=1.3