To solve the equation \(\frac{m}{2} - 9 = -21\), we need to isolate the variable \(m\). First, add 9 to both sides of the equation to eliminate the constant term on the left side. Then, multiply both sides by 2 to solve for \(m\).
Step 1: Isolate the variable term
Start with the equation:
\[
\frac{m}{2} - 9 = -21
\]
Add 9 to both sides to isolate the term with the variable:
\[
\frac{m}{2} - 9 + 9 = -21 + 9
\]
\[
\frac{m}{2} = -12
\]
Step 2: Solve for \( m \)
Multiply both sides by 2 to solve for \( m \):
\[
2 \cdot \frac{m}{2} = 2 \cdot (-12)
\]
\[
m = -24
\]