∵a= ,
∴a﹣1= ,
∴(a﹣1)2=2,即a2﹣2a+1=2,
∴a2﹣2a=1,
∴3a2﹣6a=3,
∴3a2﹣6a﹣1=2.
請你根據(jù)小明的解答過程,解決下面的問題:
若a= ,求2a2﹣12a+1的值.
聰明的小明同學(xué)根據(jù)上述材料,做了這樣的解答:
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所以
所以 , 所以
所以 , 所以 , 所以
請你根據(jù)上述材料和小明的解答過程,解決如下問題:
的有理化因式是,;
;
【感悟】
在二次根式的運(yùn)算中,需要運(yùn)用分式的基本性質(zhì),將分母轉(zhuǎn)化為有理數(shù),這就是分母有理化.像上述解題過程中與 , 與相乘的積都不含二次根式,我們可以將這兩個(gè)式子稱為互為有理化因式.
①;
②