If (x^{2} – kx + 9 = 0) has equal roots, find the values of k.
-
A.
3, 4 -
B.
(pm3) -
C.
(pm5) -
D.
(pm6)
Correct Answer: Option D
Explanation
For equal roots, we have that (b^{2} = 4ac), so, given a=1, b = -k and c = 9,
((-k)^{2} = 4times1times9 implies k^{2} = 36)
(k = sqrt{36} = pm6)