试根,1,-1等带入,分解出一个因式,再除
http://zhidao.baidu.com/link?url=_Ah2xKokgPLbo0jRT83Z_PJXhF6nOdifKecwpfu4lSOdDg8d37iHplCoE0VrjegiMoZaeARnuRCSYBI1ForIHq
下面这个你多半不想看
http://zhidao.baidu.com/question/41169178.html?qbl=relate_question_0&word=%D2%BB%D4%AA%C8%FD%B4%CE%B7%BD%B3%CC%D4%F5%C3%B4%BF%EC%CB%D9%D2%F2%CA%BD%B7%D6%BD%E2