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Question
Find the values of k for which the given quadratic equation has real and distinct roots:
`9x^2+3kx+4=0`
Solution
The given equation is `9x^2+3kx+4=0`
∴`D=(3k)^2-4xx9xx4=9k^2-144`
The given equation has real and distinct roots if` D>0`
∴`9k^2-144>0`
⇒`9(k^2-16)>0`
⇒`(k-4)(k+4)>0`
⇒`k<-4 or k>4`
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Relationship Between Discriminant and Nature of Roots
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