问题
单项选择题
设(1+ax)8=b0+b1x+b2x2+…+b8x8，若b3，b4，b5成等差数列，则a的值为（）。
A.A
B.B
C.C
D.D
答案
参考答案：C
解析：
由已知，得
即
故2a2-5a+2=0，(2a-1)(a-2)=0
解得a=
或a=2
故正确答案为C。
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设(1+ax)8=b0+b1x+b2x2+…+b8x8，若b3，b4，b5成等差数列，则a的值为（）。
A.A
B.B
C.C
D.D
参考答案：C
解析：
由已知，得
即
故2a2-5a+2=0，(2a-1)(a-2)=0
解得a=或a=2
故正确答案为C。
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| Hello, my friends! I'm Mary. This is my grandfather. He is sixty-two. He likes vegetables. This is my grandmother. She's fifty-eight. She likes noodles. Look at this young man. He's my uncle. He's twenty-nine. He likes hamburgers very much. And this is my aunt. She's thirty-seven. She likes fish.
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