x = 3a solution of the equation 3x2 + (k − 1)x + 9 = 0

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x = 3a solution of the equation 3x² + (k − 1)x + 9 = 0 if k has value

1. 13
2. −13
3. 11
4. −11

Correct Option: D

The given quadratic equation 3x² + (k − 1)x + 9 = 0
Putting x = 3 in above given eq. , we get
27 + 3(k − 1) + 9 = 0
⇒ 27 + 3k - 3 + 9 = 0
⇒ 3k = −33 ⇒ k = −11.
Hence , the value of k is −11.