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(全国Ⅰ卷理5)已知等差数列满足,,则它的前10项的和( )
A.138 B.135 C.95 D.23
已知等差数列满足,,则它的前10项的和_____
已知等差数列满足,,则它的前10项的和=( )
A.138 B.135 C.95 D.23
已知等差数列满足,,则它的前10项的和
已知等差数列满足, ,则它的前10项和 ( )