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प्रश्न
If 3 is one of the roots of the quadratic equation kx2 − 7x + 12 = 0, then k = ______.
विकल्प
1
−1
3
−3
उत्तर
If 3 is one of the roots of the quadratic equation kx2 − 7x + 12 = 0, then k = 1.
Explanation:
The given quadratic equation is kx2 − 7x + 12 = 0
∴ Put x = 3
∴ k(3)2 − 7(3) + 12 = 0
∴ 9k − 21 + 12 = 0
∴ 9k − 9 = 0
∴ 9k = 9
∴ k = `9/9`
∴ k = 1
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