Resposta :
Vc tem q deixar de bases iguais através de mmc
Mmc entre 4 e 12 = 12
3/4 = 9/12
5/12= 5/12
9/12-5/12=4/12=1/3
Mmc entre 4 e 12 = 12
3/4 = 9/12
5/12= 5/12
9/12-5/12=4/12=1/3