`MSC : 105`
`1/3=(1xx35)/(3xx35)= 35/105`
`3/5 = (3xx21)/(5xx21)= 63/105`
`3/7 =(3xx 15)/( 7xx15)= 45/105`
`=> 1/3;3/7;3/5`
`=>C`
1/3 , 3/7 , 3/5 (MSC là 105)
1/3 = 105:3x1/105=35/105
3/7 = 105:7x3/105=45/105
3/5=105:5x3/105=63/105
vậy ta sẽ có 35/105-45/105-63/105 suy ra 1/3-3/7-3/5