作业帮已知a（a-1）+（b-a²）=-7,求[（a²+b²）/2]-ab的值
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已知a（a-1）+（b-a²）=-7,求[（a²+b²）/2]-ab的值
已知a（a-1）+（b-a²）=-7,求[（a²+b²）/2]-ab的值
已知a（a-1）+（b-a²）=-7,求[（a²+b²）/2]-ab的值
a(a-1)+(b-a^2)=-7
a^2-a+b-a^2=-7
a-b=7
(a^2+b^2)/2-ab
=[(a-b)^2+2ab]/2-ab
=(49+2ab)/2-ab
=49/2+ab-ab
=49/2
a（a-1）+（b-a²）=-7
a²-a+b-a²=-7
b-a=-7
[（a²+b²）/2]-ab
=(a²-2ab+b²)/2
=(b-a) ²/2
=49/2
a^2 - a + b - a^2 = -7
a - b = 7
被求式可变形为： (a -b）^2 / 2 = 49/2