0.316-3y=4.5-0.8(y-9)

0,316-3y=4.5-0.8y+7.2
- 3y+0.8y=4.5+7.2-0.316
- 2.2y=11.384
y= -11 48/125:2 1/5
y= - 1423/125*5/11
y= - 1423/275
 y= - 5 48/275