a=2/﹙1-√3﹚=﹣﹙√3+1﹚
﹙a²-1﹚/﹙a-1﹚+√﹙a²+2a+1﹚/﹙a²+a﹚-1/a
=a+1-1/a-1/a
=a+1-2/a
=﹣√3-1+1+2/﹙√3+1﹚
=﹣√3+√3-1
=﹣1.