One more time...
Nowadays pretty much all cables are 75 Ohm. In the past, some audio cables were 50 Ohm but it's easier and more economical to just make all cables from the same 75 Ohm stock and change the color on the RCA plug.
In other words, the only difference between a 75 Ohm 'video' cable and a cable marked as 'subwoofer' cable is the color of the boot around the RCA plug...and your equipment neither knows nor cares what color it is.