1. Problem: Solve for $x$ in the equation $x + 3y = 11$. 2. Formula: To solve for $x$, isolate $x$ on one side of the equation. 3. Steps: 1. Start with the equation: $x + 3y = 11$ 2. Subtract $3y$ from both sides to isolate $x$: $$x + \cancel{3y} - \cancel{3y} = 11 - 3y$$ 3. Simplify: $$x = 11 - 3y$$ 4. Explanation: We moved the term with $y$ to the right side by subtracting it from both sides, leaving $x$ alone on the left. Final answer: $$x = 11 - 3y$$