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问题 解答题

化简求值：若4x2+4x+y2-6y+10=0，试求（x2+2y2+3）（x2+2y2-3）-（x-2y）2（x+2y）2的值．

答案

∵4x2+4x+y2-6y+10=0，

∴4x2+4x+1+y2-6y+9=0，

∴（2x+1）2+（y-3）2=0，

∴2x+1=0，y-3=0，

∴x=-

1
2
，y=3，

∴原式=（x2+2y2）2-9-（x2-4y2）2

=（x2+2y2+x2-4y2）（x2+2y2-x2+4y2）-9

=6y2×（2x2-2y2）-9

=12y2（x2-y2）-9

=12×9×（-

35
4
）-9

=-995-9

=-1004．

多项选择题

吴某是甲公司的法定代表人，吴某依据相关规定将厂房设计任务委托给符合相应资质的乙设计院，设计院指派注册建造师赵某负责该项目。由丙施工企业分三期承建，由注册建造师王某任该项目负责人，且双方约定，如丙公司前两期的工程不能在规定的时间里完成，则合同终止。

法律关系内容的变更包括( )。

A．客体内容的变更

B．客体数目的变更

C．客体范围的变更

D．客体性质的变更

E．客体形式的变更
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填空题



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