[x+1-15/(x-1)]÷[(x^2-4x)/(x^2-x)]
=[(x^2-1-15)/(x-1)]÷[x(x-4)/x(x-1)]
=[(x^2-16)/(x-1)]÷[(x-4)/(x-1)]
=[(x+4)(x-4)/(x-1)]×[(x-1)/(x-4)]
=x+4
当x=√3-4时,原式=√3-4+4=√3