Add 9 to both sides of the equation: $\displaystyle{{x}}^{{2}}-{2}{x}+{9}={0}\usepackage{cmbright}\Huge\$

Substitute $\displaystyle{a}={1},{b}=-{2}\usepackage{cmbright}\Huge\$ , and $\displaystyle{c}={9}\usepackage{cmbright}\Huge\$ into the Quadratic Formula: $\displaystyle{x}=\frac{{-{b}\pm\sqrt{{{{b}}^{{2}}-{4}{a}{c}}}}}{{{2}{a}}}\usepackage{cmbright}\Huge\$

$\displaystyle{x}=\frac{{-{\left(-{2}\right)}\pm\sqrt{{{{\left(-{2}\right)}}^{{2}}-{4}{\left({1}\right)}{\left({9}\right)}}}}}{{{2}\cdot{1}}}=\frac{{{2}\pm\sqrt{{{4}-{36}}}}}{{2}}=\frac{{{2}\pm\sqrt{{-{32}}}}}{{2}}\usepackage{cmbright}\Huge\$

$\displaystyle=\frac{{{2}\pm\sqrt{{16}}\sqrt{{-{2}}}}}{{2}}=\frac{{{2}\pm{4}\sqrt{{2}}{i}}}{{2}}=\frac{{2}}{{2}}\pm\frac{{{4}\sqrt{{2}}}}{{2}}{i}={1}\pm{2}{i}\sqrt{{2}}\usepackage{cmbright}\Huge\$