12. Given the function $f(x)=2+\log _{3} x, x \in[1,9]$, then the range of $y=[f(x)]^{2}+f\left(x^{2}\right)$ is
12. $[6,22]$ Let $t=\log _{3} x$, then $t \in[0,2], y=(2+t)^{2}+2+2 t=t^{2}+6 t+6 \in[6,22]$.