(2012^2+2014^2-2)/2013^2
=(2012²-1+2014²-1)/2013²
=[(2012-1)(2012+1)+(2014-1)(2014+1)]/2013²
=(2011×2013+2013×2015)/2013²
=2013×(2011+2015)/2013²
=4026/2013
=2