8a + 8b

_______
12c + 12d

factor to a + b
_______
c + d
Is this right?

No, what happend to the 8/12 ?

would it be 2 (4a + 4b)
_____________
6 (2c + 2d)

Is this right???

No. what about ..lets see, 8/12 reduces to 2/3, so
2(a+b)/3(c+d)