(x+1)(x+2)(x+3)(x+4)-48
=[(x+1)(x+4)]*[(x+2)(x+3)]-48
=(x^2+5x+4)(x^2+5x+6)-48
=(x^2+5x)^2+10(x^2+5x)-24
=(x^2+5x+12)(x^2+5x-2)
解此题时x^2+5x是关键.
(x+1)(x+2)(x+3)(x+4)-48
=[(x+1)(x+4)]*[(x+2)(x+3)]-48
=(x^2+5x+4)(x^2+5x+6)-48
=(x^2+5x)^2+10(x^2+5x)-24
=(x^2+5x+12)(x^2+5x-2)
解此题时x^2+5x是关键.