Tolonhg jawab y suah bngt sy bingung nih..... plis...

a. 2/15 - 1/2 + 3/10
= (2.2)/30 - (15.1)/30 + (3.3)/30
= 4/30 - 15/30 + 9/30
= 13/30 - 15/30
= -2/30
= -1/15


b.3/7 + 4/21 - 13/14
= (6.3)/42 + (2.4)/42 - (3.13)/42
= 18/ 42 + 8/42 - 39/42
= -13/42

c