Find the roots of quadratic equation: x2 + x - 42 = 0?
Correct answer: D. -7, 6
- A. -6, 7
- B. -8, 7
- C. 14, -3
- D. -7, 6
Explanation
The quadratic factors as x² + x - 42 = (x + 7)(x - 6) = 0. Hence the roots are x = -7 and x = 6. The likely trap is -6 and 7, obtained by reversing both signs while factoring the constant product.
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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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