Question

已知y=x^2-2x+1/x^2-1除以x^2-x/x+1-1/x+1,

Answer 1

y=[(x-1)^2/(x+1)(x-1)]÷[x(x-1)/(x+1)]-1/x+1

=[(x-1)/(x+1)]×[(x+1)/x(x-1)]-1/x+1

=1/x-1/x+1

=1

所以不论x为何值,y值都不变