见下图,格式也请规范,
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/06/22 09:08:59
见下图,格式也请规范,
![](http://img.wesiedu.com/upload/1/92/192a4c8d552a650095a3bd902e6f1da8.jpg)
![](http://img.wesiedu.com/upload/1/92/192a4c8d552a650095a3bd902e6f1da8.jpg)
![见下图,格式也请规范,](/uploads/image/z/6223772-20-2.jpg?t=%E8%A7%81%E4%B8%8B%E5%9B%BE%2C%E6%A0%BC%E5%BC%8F%E4%B9%9F%E8%AF%B7%E8%A7%84%E8%8C%83%2C)
a²+a-1=0→a²+a=1→a²=1-a
a³+2a²+2007
=a²(a+2)+2007
=(1-a)(a+2)+2007 (a²=1-a)
=a+2-a²-2a+2007
=-(a²+a)+2009
=-1+2009
=2008
a³+2a²+2007
=a²(a+2)+2007
=(1-a)(a+2)+2007 (a²=1-a)
=a+2-a²-2a+2007
=-(a²+a)+2009
=-1+2009
=2008