Applications of Linear Inequalities
Linear inequalities help solve real-world problems with constraints. For example, if a vendor sells hot dogs for 4andhamburgersfor5, and needs to make at least $1,000 in sales, we can write this as 4x + 5y ≥ 1000, where x represents hot dogs and y represents hamburgers.
By rearranging to y ≥ -4/5x + 200, we can graph this inequality. The boundary line is y = -4/5x + 200, and we shade above since the inequality is ≥. The shaded region shows all possible combinations of hot dogs and hamburgers that would generate at least $1,000 in sales.
The graph helps visualize that if the vendor sells no hamburgers y=0, they would need to sell at least 250 hot dogs to reach the goal. Similarly, if they sell no hot dogs x=0, they'd need to sell at least 200 hamburgers.
Pro tip: When solving real-world problems, pay attention to context constraints. For example, in this problem, you can't sell negative amounts of food, so the solution is limited to the first quadrant (where x ≥ 0 and y ≥ 0).