Respuesta :

Answer:  -5/21

Step-by-step explanation:

-3/7 & -4/6

common detonator is 42

-3/7 = -18/42 reduced to -9/21

-4/6 = -28/42 reduced to -14/21

difference between -9/21 and -14/21 = -5/21

RELAXING NOICE
Relax