1. The problem is to solve for $x$ in the equation $x + 5 = 12$. 2. The formula used here is to isolate $x$ by subtracting 5 from both sides of the equation. 3. Subtract 5 from both sides: $$x + 5 - 5 = 12 - 5$$ 4. Simplify both sides: $$x = 7$$ 5. Therefore, the solution to the equation is $x = 7$.