Find the roots of the quadratic equation: 2×2 + 3x - 9 = 0?
Correct answer: B. 3/2, -3
- A. 3, -3/2
- B. 3/2, -3
- C. -3/2, -3
- D. 3/2, 3
Explanation
For 2x^2 + 3x - 9 = 0, factorisation gives (2x - 3)(x + 3) = 0. Hence x = 3/2 or x = -3. The likely trap is option a, which incorrectly uses 3 instead of 3/2 for the positive root.
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Quadratic equations contain a squared variable and can be solved by factorisation, completing the square, the quadratic formula, or graphical reasoning. Questions cover roots, the discriminant, and the relationship between roots and coefficients, while distinguishing real and repeated roots from complex or non-real roots.
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