向二楼那位兄台所说,令2012=a.
原式=(a³-2a²-a+2)/(a³+a²-a-1)
=[a²(a-2)-(a-2)]/(a³-a+a²-1)
=(a²-1)(a-2)/[a(a²-1)+(a²-1)]
=(a²-1)(a-2)/(a+1)(a²-1)
=(a-2)/(a+1)
=2010/2013