If one root of the equation x2 + px + 12 = 0 is 4, while the equation x2 + px + q = 0 has equal roots, then the value of q is
(a) 3 

(b) 12 

(c) 49/4 

(d) 4.

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1 Answers

(c) : As x2 + px + q = 0 has equal roots ∴ p2 = 4q and one root of x2 + px + 12 = 0 is 4.
∴ 16 + 4p + 12 = 0 ∴ p = –7
∴ p2 = 4q => q =49/4

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