In inequality graphs, what does a solid line or filled circle indicate?

In inequality graphs, what does a solid line or filled circle indicate?

• A. solid line or filled in circle
• B. dashed line or open circle
• C. no line is used
• D. a dotted line with hollow circle

Answer: (A)

In inequality graphs, the boundary line shows where the inequality switches from true to false. A solid boundary means the value on the boundary is included in the solution. That’s why a solid line or a filled circle indicates inclusion—the inequality uses ≤ or ≥, so every point on the boundary, and the points on the chosen side, satisfy the inequality. If the boundary were dashed or the circle open, the boundary value wouldn’t be included, matching < or > instead.

In inequality graphs, the boundary line shows where the inequality switches from true to false. A solid boundary means the value on the boundary is included in the solution. That’s why a solid line or a filled circle indicates inclusion—the inequality uses ≤ or ≥, so every point on the boundary, and the points on the chosen side, satisfy the inequality. If the boundary were dashed or the circle open, the boundary value wouldn’t be included, matching < or > instead.