x3-14x+5=x（x2-14x）+5
∵x2-3x-5=0，
∴x2=3x+5，
∴x3-14x+5=x（3x+5-14）+5
=x（3x-9）+5
=3x2-9x+5
=3（3x+5）-9x+5
=9x+15-9x+5
=20．
猜你喜欢
- 1miss smith is a friend of mary‘s mother’s
- 2高中英语选择in order to curb property prices,the government had just made a new policy_____
- 3words___me when I wated to express my thanks to him for having given me so much help
- 4first of all,first,at first,和firstly的区别
- 5who told you to clean the window?father（）.he said they are too dirty Atold Bdid Ctelling
- 6if any ;if some if ever ;if never 区别,要例句
- 7Cindy has a tennis racket.改为否定句
- 8万物生长靠太阳,太阳得六种做用是什么
- 9为什么用排水法收集氧气在水中的集气瓶要到放?氧气的密度不是比空气大么,为什么可以在水中集气瓶的底
- 10“4.14”青海玉树地震后，南京市立即组织医护工作人员赶赴玉树灾区参加伤员抢救工作．派30名医护人员，携带20件行李（药品、器械），租用甲、乙两种型号的汽车共8辆，日夜兼程赶赴灾