w90888
花朵
共回答了23个问题采纳率:87% 举报
1.
2010×2010/2009
=(2009+1)²/2009
=(2009²+2×2009×1+1²)/2009
=2009²/2009+2×2009×1/2009+1²/2009
=2009+2+1/2009
=2011又1/2009
2.
13×(5/26+5/22)×4/11
=13×(5/26)×(4/11)+13×(5/22)×(4/11)
=(5/2)×(4/11)+13×(5/11)×(2/11)
=10/11+(10/11)×(13/11)
=(10/11)(1+13/11)
=(10/11)(24/11)
=240/121
1年前
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