\[\frac{1}{3}x^{2} - 2x + 5 =\]
\[= \frac{1}{3} \cdot \left( x^{2} - 6x + 15 \right) =\]
\[= \frac{1}{3} \cdot \left( x^{2} - 6x + 9 + 6 \right) =\]
\[= \frac{1}{3} \cdot (x - 3)^{2} + 2\]