(x+1)(x+2)(x+3)(x+4)-8=[(x+1) (x+4)][ ( x+2)(x+3)] -8=(x^2+5x+4)(x^2+5x+6) -8=(x^2+5x)^2+10(x^2+5x)+24-8=(x^2+5x)^2+10(x^2+5x)+16=(x^2+5x+2) (x^2+5x+8)