Example

Solving {y<3x+2,  y>x1}\{y < 3x + 2,\; y > -x - 1\} by Graphing

Solve the system {y<3x+2y>x1\left\{\begin{array}{l} y < 3x + 2 \\ y > -x - 1 \end{array}\right. by graphing.

Step 1 — Graph y<3x+2y < 3x + 2. The boundary line is y=3x+2y = 3x + 2. Because the inequality uses << (strict), draw a dashed line. Test (0,0)(0, 0): 0<3(0)+20 < 3(0) + 2 gives 0<20 < 2, which is true, so shade the side of the line that contains the origin.

Step 2 — Graph y>x1y > -x - 1 on the same grid. The boundary line is y=x1y = -x - 1. Because the inequality uses >> (strict), draw a dashed line. Test (0,0)(0, 0): 0>010 > -0 - 1 gives 0>10 > -1, which is true, so shade the side that contains the origin.

Step 3 — Identify the solution. The solution is the area where both shaded regions overlap. The intersection point of the boundary lines is not included because both boundary lines are dashed.

Step 4 — Verify with a test point. Choose a test point in the overlapping region and substitute it into both inequalities to confirm both are true.

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Updated 2026-04-28

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