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Question
Find k, one of the roots of the quadratic equation kx2 - 7x + 12 = 0 is 3.
Solution
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
∴ k = `9/9`
∴ k = 1
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