Answer
$\frac{13}{24}$
Work Step by Step
First, we want to find a common denominator. This needs to be a multiple of both 12 and 8. The smallest number that satisfies this is 24.
Rewriting the fractions so that the denominators are both 24, the expression we are trying to evaluate becomes
$\frac{11*2}{12*2}-\frac{3*3}{8*3}$. Simplifying:
$\frac{11*2}{12*2}-\frac{3*3}{8*3}$
=$\frac{22}{24}-\frac{9}{24}$
=$\frac{22-9}{24}$
=$\frac{13}{24}$.