311/15:[2/1-22/5*(5/9-1/2)]=
22/5=2*5+2/5=12/5
311/13:[2/1-12/5*(5/9-1/2)]=
5/9 il amplificam cu 2=10/18
1/2 il amplificam cu 9=9/18
311/15:[2/1-12/5*(10/18-9/18)]=
10/18-9/18=1/18
311/15:(2/1-12/5*1/18)=
12/5*1/18=12/90
311/15:(2/1-12/90)=
2/1 il amplificam cu 90=180/90
311/15:(180/90-12/90)=
180/90-12/90=168/90
311/15:168/90⇒311/15*90/168=
simplificam 15 cu 90⇒311/1*6/168=1866/168
Sper ca te-am ajutat