1. **State the problem:** Solve the linear equation $2x - 4y = 20$ for $y$ in terms of $x$. 2. **Formula and rules:** To solve for $y$, isolate $y$ on one side of the equation. This involves moving terms and dividing by the coefficient of $y$. 3. **Isolate $y$:** $$2x - 4y = 20$$ Subtract $2x$ from both sides: $$-4y = 20 - 2x$$ 4. **Divide both sides by $-4$ to solve for $y$:** $$y = \frac{20 - 2x}{-4}$$ Show cancellation: $$y = \frac{\cancel{20} - \cancel{2}x}{\cancel{-4}} = \frac{20}{-4} - \frac{2x}{-4}$$ 5. **Simplify each term:** $$y = -5 + \frac{1}{2}x$$ 6. **Rewrite in standard form:** $$y = \frac{1}{2}x - 5$$ **Final answer:** $$y = \frac{1}{2}x - 5$$