How do I go from $33/64 - 2x + x^2 \longrightarrow \bigg(x - \frac{2 + \sqrt{4 +33/16}}{2}\bigg)\bigg(x - \frac{2 - \sqrt{4 +33/16}}{2}\bigg)$? 
How do I go from $\frac{33}{64} - 2x + x^2 \longrightarrow\bigg(x - \frac{2 + \sqrt{4 +33/16}}{2}\bigg)\bigg(x - \frac{2 - \sqrt{4 +33/16}}{2}\bigg)$ and then to $\big(x - 1-\frac{\sqrt{33}}{8}\big)\big(x - 1 + \frac{\sqrt{31}}{8}\big)?$

For the first, I know that it has something with the quadratic equation to do, but what is that? And how do I go from the second to the third?

$$
\begin{align}
&\frac{33}{64} - 2x + x^2 \\
&= x^2 - 2x + \frac{33}{64} \\
&= x^2 - 2x + 1 - 1 + \frac{33}{64} \\
&= (x-1)^2 - 31/64 \\
&= (x-1)^2 - 31/64 \\
&= (x-1)^2 - 31/64 \\
&= \left( (x-1) - \sqrt{31}/8 \right)\cdot\left( (x-1) + \sqrt{31}/8 \right) \\
&= \color{red}{\left( x-1 - \sqrt{31}/8 \right)\cdot\left( x-1 + \sqrt{31}/8 \right)} \\
&= \left( x-\frac {2 + \sqrt{31}/4}2 \right)\cdot\left( x-\frac{2 - \sqrt{31}/4}{2} \right) \\
&= \left( x-\frac {2 + \sqrt{31/16}}2 \right)\cdot\left( x-\frac{2 - \sqrt{31/16}}{2} \right) \\
& = \left(x - \frac{2 + \sqrt{4 \color{red}-33/16}}{2}\right)\cdot\left(x - \frac{2 - \sqrt{4 \color{red}-33/16}}{2}\right)
\end{align}
$$
Please note the minus inside square roots!
