a(a-1)-(a二次方+b)=8
a²-a-a²-b=8
-a-b=8
a+b=-8
二分之a(chǎn)二次方+b二次方-ab
=1/2(a²+b²-2ab)
=1/2(a-b)²
=1/2x(-8)²
=32
如追加其它問(wèn)題,采納本題后點(diǎn)擊想我求助,不好意思那個(gè)不是等于8是等于-8打錯(cuò)了 求糾正a(a-1)-(a二次方+b)=-8a²-a-a²-b=-8-a-b=-8a+b=8二分之a(chǎn)二次方+b二次方-ab=1/2(a²+b²-2ab)=1/2(a-b)²=1/2x8²=32