If 3 is a zero of polynomial 2x2 + x + k, then value of k will be(A) – InterviewSolution

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1.

If 3 is a zero of polynomial 2x2 + x + k, then value of k will be(A) 12(B) 21(C) 24(D) -21

Answer»

Answer is (D) -21

Let f(x) = 2x² + x + k

One zero is 3

f(3) = 0

⇒ 2(3)² + 3 + k = 0

⇒ 2 × 9 + 3 + k = 0

⇒ 18 + 3 + k = 0

⇒ k = -21

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