If we take the equation and multiply out the left side, we get....
[tex] x^{2} [/tex] + 2xk + [tex] k^{2} [/tex] = [tex] x^{2} [/tex] + x +[tex] k^{2} [/tex]
The x^2 and k^2 cancel out on both sides leaving us with this...
2kx = x
If we divide both sides by 2x to isolate k, k ends up = 1/2
