their nervous systems and ability to produce baby birds, and can lead to kidney(肾) failures and death. So condors with high levels of lead are sent to Los Angeles Zoo, where they are treated with calcium EDTA, a chemical that removes lead from the blood over several days. This work is starting to pay off. The annual death rate for adult condors has dropped from 38% in 2000 to 5.4% in 2011. 16.2.1二次根式的乘除
预习案
预习目标
理解a·b＝ab（a≥0，b≥0），ab=a·b（a≥0，b≥0）. 一、旧知回顾
1、二次根式的乘法：a?b?.（a?0,b?0）、、 2、积的算术平方根性质：ab??.a?0,b?0
23、利用二次根式的性质：(a)?，a?a?(a?0)，
a2?可以化简二次根式.
二、教材助读
1.计算：3?4?. 7?8? 2.计算：9?6?.4?16?.
3.完成课本“做一做”，请问发现了什么？得到什么结论？
4.通过对课本中“议一议”的思考学习，你发现了什么规律？
their nervous systems and ability to produce baby birds, and can lead to kidney(肾) failures and death. So condors with high levels of lead are sent to Los Angeles Zoo, where they are treated with calcium EDTA, a chemical that removes lead from the blood over several days. This work is starting to pay off. The annual death rate for adult condors has dropped from 38% in 2000 to 5.4% in 2011.
三、预习检测
1.计算（1）2?32（2）1?8 （3）2a?8a?a?0? 22.化简（1）9?16 （2）16?81 （3）81?100 3.化简：ab(a?0,b?0)=. 我的疑惑
把你在本次课程学习中的困惑与建议填写在下面,与同学交流后,由组长整理后并拍照上传平台讨论区.
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八年级数学下册第十六章二次根式16.2二次根式的乘除16.2.1二次根式的乘除预习学案新版新人教版
