\[(x - 5)^{2} + \left| x^{2} - 9x + 20 \right| = 0\]
\[(x - 5)^{2} \geq 0;\ \ \ \ \]
\[\left| x^{2} - 9x + 20 \right| \geq 0 \Longrightarrow сумма\ \]
\[равна\ 0,\ если\ оба\ \]
\[выражения\ равны\ 0.\]
\[x - 5 = 0\]
\[x = 5.\]
\[x^{2} - 9x + 20 = 0\]
\[D = ( - 9)^{2} - 4 \cdot 1 \cdot 20 =\]
\[= 81 - 80 = 1\]
\[x_{1} = \frac{9 + \sqrt{1}}{2} = \frac{9 + 1}{2} = \frac{10}{2} = 5\]
\[x_{2} = \frac{9 - \sqrt{1}}{2} = \frac{9 - 1}{2} = \frac{8}{2} = 4\]
\[Ответ:x = 5.\]