kx² + 8x + 8 = 0
We want this to have just one solution, we know this equation:
x = (-b ± √Δ)/2a
So if Δ = 0 we have just one solution.
Δ = b² - 4.a.c
0 = 8² - 4.k.8
0 = 64 - 32k
32k = 64
k = 2
2x² + 8x + 8 = 0
x² + 4x + 4 = 0
(x + 2)² = 0
x + 2 = 0
x = -2
The solution is -2.
