已知x²-5x-1997=0,求代数式[(x-2)³-(x-1)²+1]/(x-2)
问题描述:
已知x²-5x-1997=0,求代数式[(x-2)³-(x-1)²+1]/(x-2)
答
∵x²-5x-1997=0∴x²=5x+1997∴[(x-2)³-(x-1)²+1]/(x-2)=(x-2)²-[(x-1)²-1]/(x-2)又(x-2)²=x²-4x+4=5x+1997-4x+4=x+2001(x-1)²-1=x²-2x=5x+1997-2x=3x+1997∴原...