28(3/28-9/14)= 15(1 2/5-1 14/15)= 7 14/15 : 3 2/5= 3 3/10 : 1 1/2 =

-28(3/28-9/14)=-28*(-15/28)=15

15(1 2/5-1 14/15)=15*(7/5-29/15)=15*(21/15-29/15)=15*(-8/15)=-8

7 14/15 :3 2/5=119/15*5/17=7/3=2 1/3

3 3/10 : 1 1/2 =33/10*2/3=11/5=2 1/5