121.3二次根式的加减第2课时二次根式的混合运算2163483(2)(1220)(35)21(3)96234xxxx(1)2124528200(2)22034580(3)248(27243)(4)(575412)(5108327)计算:(1)75253.细心算一算)432276(32)3()4554513()54180)(2()723250811()25.028)(1(32aabababa6观察下面两个题目的计算过程7试一试1273623233683482738123(25)()()(2)53(53)()计算解:原式22325215222151322解:原式2253532923325()()解:原式2252523239125201252910(2233)(3322)(22)(322)(1)(2)解:(1)原式22223382719642324(2)原式22112232,32.abaabb已知,求的值2232323232解:原式52632526526152699想一想:还有其他方法吗?1222222aabbaabbab解二:2()abab232323232222181913通过本节课的学习,谈谈你有哪些收获.14