第2个回答 2011-02-23
1.(x+1)*(x+2)*(x+3)*(x+4)-120
=(x+1)*(x+4)*(x+2)*(x+3)-120
=(x²+5x+4)(x²+5x+6)-120
=(x²+5x)²+10(x²+5x)+24-120
=(x²+5x)²+10(x²+5x)-96
=(x²+5x+16)(x²+5x-6)
=(x²+5x+16)(x+6)(x-1)
2.(x-1)*(x-3)*(x+1)*(x+3)-20
=.(x-1)*(x+1)*(x-3)*(x+3)-20
=(x²-1)(x²-9)-20
=(x²)²-10x²+9-20
=(x²)²-10x²-11
=(x²-11)(x²+1)
=(x+√11)(x-√11)(x²+1)