先化简,再求值:(x2-3/x-1-2)除以1/x-1,其中x满足x2-4x+3=0.
问题描述:
先化简,再求值:(x2-3/x-1-2)除以1/x-1,其中x满足x2-4x+3=0.
答
x2-4x+3=0
∴(x-3)(x-1)=0
∵x-1≠0
∴x-3=0
∴x=3
:(x2-3/x-1-2)除以1/x-1
=(x²-3-2x+2)/(x-1)×(x-1)
=x²-2x-1
=9-6-1
=2