Answer
Yes, $4$ is a factor of $2a\times34b$, because $2a\times34b=2a\times(2\times17)b=4(a\times17b)$, where $a\times17b$ is an integer because it is a product of integers.
Work Step by Step
Note that "is a factor of" means the same thing as "divides." Further, recall that $a|b$ for integers $a$ and $b$ with $a\ne0$, if and only if $b=ka$ for some integer $k$. Here, $k=a\times17b$.
