Use the Squeeze Theorem to evaluate the limit $\displaystyle{ \lim_{x\to 3} f(x) }$ if $${6} x - {9} \leq f(x) \leq x^2$$ on the interval $[{1}, {5}]$. $\displaystyle{ \lim_{x\to 3} f(x) = }$ Enter DNE if the limit does not exist.