中等MATH-INEQ-003
Solve x^2 − 5x + 6 < 0.
A. x < 2 or x > 3
B. x ≤ 2 or x ≥ 3
C. 2 ≤ x ≤ 3
D. 2 < x < 3✓ 答案
解說
(x − 2)(x − 3) is negative between the roots, so 2 < x < 3. The region outside the roots is where the quadratic is positive. The endpoints make the expression zero, so they are excluded by the strict inequality.