\[x^{2} - 12x + 38 = x^{2} - 12x + 36 + 2 =\]
\[= (x - 6)^{2} + 2 > 0\ при\ любом\ x,\ \]
\[так\ как\ (x - 6)^{2} \geq 0;\ \ 2 > 0.\]