Answer
It is a factor of $f(x).$
Work Step by Step
The Remainder Theorem says that the remainder when a function $f(x)$ is divided by $(x-r)$ is $f(r)$.
Hence $f(2)=3\cdot16-6\cdot8-5\cdot2+10=0$, therefore $(x-2)$ is a factor of $f(x)$ by the Factor theorem.
The factor theorem says that if $f(c)=0$, then $(x-c)$ is a factor of $f(x)$ and vice versa.