12 13/45-(у- 5 17/45)= 3 23/45

12 13/45-y+5 17/45<span>=3 23/45
12 13/45+5 17/45-y</span><span>=3 23/45
17 30</span>/45-3 23/45<span>=y
y</span><span>=14 7/45</span>