1. **State the problem:** We want to find the equation representing the combinations of 6-passenger cars ($x$) and 3-passenger cars ($y$) such that the total passengers per run is at least 12. 2. **Write the inequality:** Each 6-passenger car holds 6 passengers, and each 3-passenger car holds 3 passengers. The total passengers must be at least 12: $$6x + 3y \geq 12$$ 3. **Rewrite the inequality to express $y$ in terms of $x$:** $$3y \geq 12 - 6x$$ Divide both sides by 3: $$y \geq \frac{12 - 6x}{3}$$ Show cancellation: $$y \geq \frac{\cancel{3} \times 4 - \cancel{3} \times 2x}{\cancel{3}}$$ Simplify: $$y \geq 4 - 2x$$ 4. **Interpret the inequality:** The line $y = 4 - 2x$ is the boundary. The region satisfying the inequality is all points above or on this line. 5. **Check the graphs:** - The correct graph should have a line with slope $-2$ and y-intercept 4. - The shaded region should be above this line. 6. **Conclusion:** The graph that matches this description is Graph 2 (center), which shows the line descending from $y=5$ at $x=-5$ to $y=0$ at $x=4$ with the area above the line shaded. **Final answer:** The equation is $$y \geq 4 - 2x$$ and the correct graph is Graph 2 (center).