## anonymous 4 years ago How do I solve: x^2 = kx + 1 for x by completing the square?

1. anonymous

start with $x^2-kx=1$ then $(x-\frac{k}{2})^2=1+\frac{k^2}{4}=\frac{4+k^2}{4}$

2. anonymous

then $x+\frac{k}{2}=\pm\frac{\sqrt{4+k^2}}{2}$ and finally $x=\frac{-k\pm\sqrt{4+k^2}}{2}$

3. anonymous

oohh.. o.o thank you!