However, if you really want to learn, don't tell those of us who gave you a correct answer to the question that you asked that we are wrong. The answers that you were given to the questions that you asked were correct. That you didn't understand yourself what you were asking was the problem.
The Long and the Short.
If the coils of a sub or multiple subs are wired to present a single load to a single amp channel, that amp channel will "see" whatever final load that you have the coipls wired to. This is simple series/parallel wiring.
If you were to then take the above load and bridge two amp channels into it, the final load won't cahnge, but each amp channel will "see" half of the final load. Two halves make a whole.
If you take a multiple coil sub and connect each coil to its own amp channel, each channel "sees" the load of the coil connected to it. This is bi- or Quad- amping (depending on the number of amps and coils involved).
If you take two mono amps capable of being strapped and wire them to a single load (be it a single coil or multiple coils wired together), each amp will "see" half the final load as in a bridged setup. Again two halves make a whole. This is called strapping.
Recap of terminology:
Bridging: two amp channels to a single load
Strapping: two mono amps to a single load
Bi-amping: two amps wired to a dual coil sub so that each amp or amp channel is driving its own coil. This can be combined with bridging or strapping.
Quad-amping: Wiring each coil of a quad coil sub to its own source of amplification. Like bi-amping this can be combined with bridging or strapping.
If you still aren't clear, read this over and again until you are...