1) 8/13* (-5/4)= (-10/13)
2) (-5/14)*(-28/15)= 2/3
3) -12/13* 39/14=-18/7
4)12* (-5/4)= -15
5) 19/12* (-6)= -19/2
6) -12/7* (-15/4) =45/7
