(x+1)(x+2)(x+3)(x-4)+36

(x+1)(x+2)(x+3)(x+4)+36
=[(x+1)(x+4)][(x+2)(x+3)]+36
=(x²+5x+4)(x²+5x+6)+36
=(x²+5x)²+10(x²+5x)+60
=(x²+5x)²+10(x²+5x)+25+35
=(x²+5x+5)²+35 /实数范围内无法分解,如果是复数范围,继续：
=(x²+5x+5+√35i)(x²+5x+5-√35i)