If \(x^{2} – kx + 9 = 0\) has equal roots, find the values of k.
- 3, 4
- \(\pm3\)
- \(\pm5\)
-
\(\pm6\)
The correct answer is: D
Explanation
For equal roots, we have that \(b^{2} = 4ac\), so, given a=1, b = -k and c = 9,
\((-k)^{2} = 4\times1\times9 \implies k^{2} = 36\)
\(k = \sqrt{36} = \pm6\)