-x² + x + 2 ≥ 0
-x² + 2x - x + 2 ≥ 0
-x * (x -2) - (x - 2) ≥ 0
- (x - 2) * (x + 1) ≥ 0
(x - 2) * (x + 1) ≤ 0
[tex]\left \{ {{x - 2 < 0} \atop {x+1 > 0}} \right. \\\left \{ {{x - 2 > 0 } \atop {x + 1 < 0}} \right. \\\\\left \{ {{x < 2} \atop {x > - 1}} \right. \\\left \{ {{x > 2} \atop {x < -1}} \right. \\\\\\\\[/tex]
x∈ [-1, 2]
