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已知{an}是等差数列,a1+a2=4,a7+a8=28,则该数列前10项和S1...
已知{an}是等差数列,a1+a2=4,a7+a8=28,则该数列前10项和S10等于( )
A.64
B.100
C.110
D.120
考点分析:
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