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Question
If x=3 is a solution of the equation `3x^2+(k-1)x+9=0` then k=?
(a) 11 (b)-11 (c)13 (d)-13
Solution
(b)-11
It is given that x=3 is a solution of `3x^2+(k-1)x+9=0` therefore, we have:
`3(3)^2+(k-1)xx3+9=0`
⇒ `27+3(k-1)+9=0`
⇒` 3(k-1)=-36`
⇒`(k-1)=-12`
⇒`k=-11`
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