1. **State the problem:** Solve the system of equations by substitution: $$y = 4x + 8$$ $$y = -6x - 12$$ 2. **Formula and method:** Since both expressions equal $y$, set them equal to each other: $$4x + 8 = -6x - 12$$ 3. **Solve for $x$:** $$4x + 8 = -6x - 12$$ Add $6x$ to both sides: $$4x + 6x + 8 = -6x + 6x - 12$$ $$10x + 8 = -12$$ Subtract 8 from both sides: $$10x + \cancel{8} - 8 = -12 - 8$$ $$10x = -20$$ Divide both sides by 10: $$\frac{\cancel{10}x}{\cancel{10}} = \frac{-20}{10}$$ $$x = -2$$ 4. **Find $y$ by substituting $x = -2$ into one of the original equations:** Using $y = 4x + 8$: $$y = 4(-2) + 8 = -8 + 8 = 0$$ 5. **Final answer:** $$\boxed{(x, y) = (-2, 0)}$$ This is the solution to the first system by substitution.