\[x^{2} - 6xy + 10y^{2} - 2y + 1 =\]
\[= x^{2} - 6xy + 9y^{2} + y^{2} - 2y + 1 =\]
\[= (x - 3)^{2} + (y - 1)^{2} \geq 0;\ \ \ \]
\[т.к.\ (x - 3)^{2} \geq 0\ \ \ и\ \]
\[\ (y - 1)^{2} \geq 0\]