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Asked: If 2 is a root of the equation \(x^2 + kx + 12 = 0\) and the equation \(x^2 + kx + q = 0\) has equal roots, what is the value of q?

4 + 2k + 12 = 0
k = -8

x^2 -8x + q = 0 has equal roots
q = 16


IMO C

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'2' being the root of the equation hence substitute x = 2 in the equation \(x^2 + kx + 12 = 0\)

=> \(2^2 + 2k + 12 = 0\)

=> 4 + 2K + 12 = 0

=> 2k = -16

=> k = -8

Since, \(x^2 + kx + q = 0\) or \(x^2 - 8x + q\) has equal roots. Therefore, D(b^2 - 4ac) = 0

=> a = 1 ; b = -8 ; c = q

=> \((-8)^2 - 4(1)(q) = 0\)

=> 64 = 4q

=> q = 16

Answer C
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Hi can anyone explain how the answer is D?

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Hi can anyone explain how the answer is D?

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The OA is C. Edited. Thank you.
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