9. $\frac{1}{2}(m-8)$
\boxed{\frac{1}{2}m - 4}
Step 1 :Distribute \(\frac{1}{2}\) to both terms inside the parentheses: \(\frac{1}{2}(m-8) = \frac{1}{2}m - \frac{1}{2}(8)\)
Step 2 :Simplify the expression: \(\frac{1}{2}m - \frac{1}{2}(8) = \frac{1}{2}m - 4\)
Step 3 :\boxed{\frac{1}{2}m - 4}