What is the correct condition on \(k\) for the equation \(kx^2-6x+k=0\) to have real and distinct roots?

Correct answer: \(k^2<9\) and \(k\ne0\)

Here, \(a=k\), \(b=-6\), and \(c=k\). Therefore, the discriminant is \(D=b^2-4ac=36-4k^2\). Real and distinct roots require \(D>0\), giving \(36-4k^2>0\), or \(k^2<9\). In addition, the equation must remain quadratic, so its leading coefficient must satisfy \(k\ne0\). Hence the correct condition is \(k^2<9\) and \(k\ne0\). Option B is incomplete because it allows \(k=0\), which makes the equation linear. Exam tip: for distinct real roots, impose \(D>0\) and also verify that the leading coefficient is non-zero.