1. **State the problem:** Solve the equation $3x=36$ for $x$. 2. **Formula and rule:** To isolate $x$, divide both sides of the equation by 3. The rule is that whatever you do to one side of the equation, you must do to the other side to keep it balanced. 3. **Intermediate work:** $$3x=36$$ Divide both sides by 3: $$\frac{\cancel{3}x}{\cancel{3}}=\frac{36}{3}$$ 4. **Simplify:** $$x=12$$ 5. **Answer:** The solution to the equation $3x=36$ is $x=12$.