2018 · Q6
If x² - 6x - 27 > 0, then which one of the following is correct ?
Elementary MathematicsHCF and LCM
- A- 3 < x < 9
- Bx - 3
- Cx > 9 or x < - 3
- Dx < — 3 only
Explanation
Factoring: x^2 - 6x - 27 = (x - 9)(x + 3) > 0. A product is positive when both factors have the same sign: either x - 9 > 0 and x + 3 > 0, or both negative. This gives x > 9 or x < -3. Hence option C.