-4/11*15/17-7/11*15/17= б)13/15*8/19-13/15*(8/19-10/13)
-4/11*15/17-7/11*15/17=-15/17(4/11+7/11)=-15/17*1=-15/17 б) 13/15*8/19-13/15(8/19-10/13)=13/15*8/19-13/15*8/9+13/15*10/13=13/15*10/13=10/15=2/3