1. The graph of the quadratic function $y=x^{2}-a x+2$ is symmetric about the line $x=1$. Then the minimum value of $y$ is $\qquad$ .
$$
=, 1.1 .
$$

From the condition, we know that $a=2$. Then $y=(x-1)^{2}+1$ has a minimum value of 1.