JAMB 2003 · UME · Q20

Triangle $OPQ$ in the graph is the solution of the inequalities

Worked solution (try it first)

The triangle lies to the right of the vertical line $x = -1$ , so $x + 1 \ge 0$ .
It lies below the line $y = -x$ , so $y + x \le 0$ , and above the line $y = x$ , so $y - x \ge 0$ .
Check with the point $(-0.5, 0)$ inside the triangle: $0.5 \ge 0$ , $-0.5 \le 0$ and $0.5 \ge 0$ .
So it is option B.