Answer
$6$
Work Step by Step
Let us consider $x=3.001 \implies f(x)= 6.001000; \\x=3.01 \implies f(x)= 6.01000 \\x=3.1 \implies f(x)= 6.100000$
From the computed data it has been seen that as $x$ approaches $3$ from left and right, then $f(x)$ approaches $6$, so we have:
$ LHL =\lim\limits_{x \to 3^{-}}f(x)=6$ and $ RHL =\lim\limits_{x \to 3^{-}}f(x)=6$
Since, $ LHL =RHL$
Therefore, $\lim\limits_{x \to 3}=6$