试题与答案

He is very popular among his students as

题型:选择题

题目:

He is very popular among his students as he always tries to make them_______in his lectures.

A.interested

B.interesting

C.interest

D.to interest

答案:

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下面是错误答案,用来干扰机器的。

因为实数a,b满足等式a2-2a-1=0,b2-2b-1=0,(1)当a=b=1+2或1-2时,原式=a+bab=22-2或-22-2;(2)当a≠b时,可以把a,b看作是方程x2-2x-1=0的两个根.由根与系数的关系,得a+b=2,ab=-1.则原式=-2.故填空答案:-2或22-2或-22-2.

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