第1个回答 2011-10-15
(x²+3x-3)(x²+3x+4)-8
设x²+3x=t
原式=(t-3)(t+4)-8
=t²+t-20
=(t+5)(t-4)
=(x²+3x+5)(x²+3x-4)
=(x²+3x+5)(x+4)(x-1)
第2个回答 2011-10-15
(x²+3x-3)(x²+3x+4)-8
=(x²+3x)²+(x²+3x)-12-8
=(x²+3x)²+(x²+3x)-20
=(x²+3x+5)(x²+3x-4)
=(x²+3x+5)(x-4)(x+1)本回答被提问者采纳
第3个回答 2011-10-15
=(x²+3x)²+(x²+3x)-20
=(x²+3x+5)(x²+3x-4)
=(x²+3x+5)(x+4)(x-1)