1. **State the problem:** Solve the linear equation $x + 8y = -20$ for $x$ in terms of $y$. 2. **Formula and rules:** To solve for $x$, isolate $x$ on one side of the equation by moving all other terms to the opposite side. 3. **Intermediate work:** Starting with the equation: $$x + 8y = -20$$ Subtract $8y$ from both sides: $$x = -20 - 8y$$ 4. **Explanation:** We moved $8y$ to the right side by subtracting it from both sides, which isolates $x$. This expresses $x$ as a function of $y$. **Final answer:** $$x = -20 - 8y$$