Answer: k = -9
Step-by-step explanation:
kx² - 12x - 4 = 0
In order to have exactly one solution, it must be a perfect square.
Assume k is negative and factor out a negative 1.
-1(kx² + 12x + 4) = 0
[tex]\bigg(\sqrt{kx^2}+\sqrt4\bigg)^2=0\\\\[/tex]
The middle term = 12x [tex]= 2(\sqrt{kx^2})(\sqrt4)[/tex]
12x = 4x√k
3 = √k
9 = k
-1(9x² + 12x + 4) = 0
-9x² - 12x - 4 = 0
k=-9
