first off, convert them from mixed fractions to "improper" like you saw on the previous one... then you can get their "difference"
[tex]\bf \stackrel{mixed}{9\frac{1}{8}}\implies \cfrac{9\cdot 8+1}{8}\implies \stackrel{improper}{\cfrac{73}{8}}
\\\\\\
\stackrel{mixed}{2\frac{5}{6}}\implies \cfrac{2\cdot 6+5}{6}\implies \stackrel{improper}{\cfrac{17}{6}}\\\\
-------------------------------\\\\
\cfrac{73}{8}-\cfrac{17}{6}\impliedby \textit{so our LCD is 24}\implies \cfrac{(3\cdot 73)~-~(4\cdot 17)}{24}
\\\\\\
\cfrac{219-68}{24}\implies \cfrac{151}{24}\implies 6\frac{7}{24}[/tex]
