问题
单项选择题
若a，b，c成等比数列，a，x，b和b，y，c都成等差数列，且xy≠0，则
的值为（）。
A．1
B．2
C．3
D．4
答案
参考答案：B
解析：
显然有b2=ac，a+b=2x，b+c=2y，则有
，选B。
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若a，b，c成等比数列，a，x，b和b，y，c都成等差数列，且xy≠0，则的值为（）。
A．1
B．2
C．3
D．4
参考答案：B
解析：
显然有b2=ac，a+b=2x，b+c=2y，则有，选B。
| 阅读表达。 | ||||||
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