(1+7/11)+(2+7/11X2)+(3+7/11X3)+……+(11+7/11X11)=?

题目详情

▼优质解答

答案和解析

(1+7/11)+(2+7/11X2)+(3+7/11X3)+……+(11+7/11X11)
=(1+2+3...+11)(1+7/11)
=66(1+7/11)
=66x18/11
=6x18
=108

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