已知:x^2-5x+2000=0.求代数式[(x-3)^3-(x-1)^2+1]/[x-2]的值悬赏50

问题描述:

已知:x^2-5x+2000=0.求代数式[(x-3)^3-(x-1)^2+1]/[x-2]的值悬赏50
有截的是减2000

(x-3)^3-(x-1)^2+1=x^3-9x^2+27x-27-x^2+2x-1+1=x^3-10x^2+29x-27
由于x^2-5x-2000=0 则x^2-5x=2000 则x^3-5x^2=2000x
故x^3-10x^2+29x-27=2029x-27-5x^2=2029x-27-5(5x+2000)=2004x-10027
=2004(x-2)-6019
故[(x-3)^3-(x-1)^2+1]/(x-2)=2004-6019/(x-2)
又x^2-5x-2000=0 则x=(5+5倍的根号321)/2或x=(5-5倍的根号321)/2
代入得:2004-6019/(x-2)=1872或2071.75
(根号321我约等于18了)