【1-1/x-1】除以x的平方-4x+4/x的平方-1 =（1-1/x-1）÷x-4x+4/x-1 =-1/x÷x-4x+4/x-1 =-1/x+4/x-1-4x =-1/3+4/3-1-4*3 =-1/27+4/9-1-12 =-13-1/27+12/27 =-13+11/27 =-12-16/27