Question

先化简：（3/x+1-x+1）÷(x2−4x+4)/(x+1) 然后从-1≤x≤2中选一个合适的整数作为x的值代入求值．

Answer 1

原式=[3/(x+1)-(x-1)]×(x+1)/(x²-4x+4)

=(3-x²+1)/(x+1)×(x+1)/(x-2)²

=-(x+2)(x-2)/(x+1)×(x+1)/(x-2)²

=-(x+2)/(x-2)

因为x-2=0,x+1=0

所以x不等于2,-1

所以x=0时

原式=-（0+2）/(0-2)

=1