Answer:
For k = 6 or k = -6, the equation will have exactly one solution.
Explanation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots
such that
, given by the following formulas:



If
, the equation has only one solution.
In this problem, we have that:

So




We will only have one solution if
. So





For k = 6 or k = -6, the equation will have exactly one solution.