JAMB - Mathematics (2007 - No. 17)
The solution of the quadratic inequality (x\(^2\) + x - 12) ≥ 0 is
x ≥ -3 or x ≤ 4
x ≥ 3 or x ≥ -4
x ≤ 3 or x \(\leq\) -4
x ≥ 3 or x ≤ -4
คำอธิบาย
(x\(^2\) + x - 12) ≥ 0
(x + 4)(x - 3) ≥ 0
Either x + 4 ≥ 0 implies x ≥ - 4
Or x - 3 ≥ 0 implies x ≥ 3
∴ x ≥ 3 or x \(\leq\) -4
(x + 4)(x - 3) ≥ 0
Either x + 4 ≥ 0 implies x ≥ - 4
Or x - 3 ≥ 0 implies x ≥ 3
∴ x ≥ 3 or x \(\leq\) -4