1. **State the problem:** Solve the equation $3m = 39$ for $m$. 2. **Formula and rules:** To solve for $m$, we need to isolate $m$ on one side of the equation. Since $m$ is multiplied by 3, we divide both sides by 3. 3. **Intermediate work:** $$3m = 39$$ Divide both sides by 3: $$\frac{\cancel{3}m}{\cancel{3}} = \frac{39}{3}$$ 4. **Simplify:** $$m = 13$$ 5. **Explanation:** Dividing both sides by 3 cancels the multiplication by 3 on the left side, leaving $m$ alone. On the right side, 39 divided by 3 equals 13, so $m = 13$. **Final answer:** $m = 13$