We can see both terms have a (x-2) in them.
We can also see that 8 and 2 are both even so there is a 2 in common.
This means that the gcd or hcf or whatever you call it is 2(x-2)
**Just mentioning most of the time we call it the GCD(greatest common divisor) or the GCF(greatest common factor) and almost never uses hcf :)