(x-1)(x-3)(x-5)(x-7)-9 =(x-1)(x-7)(x-3)(x-5)-9=(x²-8x+7)(x²-8x+15)-9=(x²-8x)²+22(x²-8x)+105-9=(x²-8x)²+22(x²-8x)+96=(x²-8x+6)(x²-8x+16)==(x²-8x+6...