(a+b)²=a²+2ab+b²=1
(a-b)²=a²-2ab+b²=2
俩是相减知ab=1∕4
又a²-b²=(a+b﹚﹙a-b﹚=√2
所以原式=(√2 )²-32*(1∕4)²+8*(1/4)-2=0