The PA system also includes a 12-way multicore. This allows the person doing the mixing to be in the audience. In some venues, this is impossible, and the mixer has to be beside the stage, which is not an ideal mix position, as the mixing person will have no idea what it really sounds like.
There are 11 inputs, allowing one spare, and the amplifier returns (the outputs from the mixer to the amplifiers) would be run in as separate cables. It is best to put the amplifiers close to the speakers if possible.