1. **State the problem:** Solve for $y$ in the equation $y - 18 = c$. 2. **Formula and rules:** To isolate $y$, add 18 to both sides of the equation. This uses the addition property of equality which states that adding the same number to both sides keeps the equation balanced. 3. **Intermediate work:** $$y - 18 + 18 = c + 18$$ 4. **Simplify:** $$y + \cancel{-18} + \cancel{18} = c + 18$$ 5. **Final answer:** $$y = c + 18$$ This means $y$ is equal to $c$ plus 18.