We can have more info about those fractions if we take them to share the same denominator, for that we use the minimum common multiple of 8 and 12 which is 96, so we multiply and divide each fraction for a certain number that gets the fraction to denominator 96:
9/8 = (12/12)(9/8) = 12*9/12*8 = 108/96
11/12 = (8/8)(11/12) = 8*11/8*12 = 88/96
So we can write the equivalence:
9/8 > 11/12
108/96 > 88/96
we can see that the inequality is true, there are a lot of fractions yet to have them closest, 108 to 88
