9b1b2b3的知识精选

.已知-9,a1,a2,-1四个实数成等差数列,-9,b1,b2,b3,-1五个实数成等比数列,则b2(a2-...
问题详情:.已知-9,a1,a2,-1四个实数成等差数列,-9,b1,b2,b3,-1五个实数成等比数列,则b2(a2-a1)=(    )A.8            B.-8            C.±8             D.7【回答】B知识点...
热门标签