Tính hợp lí: A=1/56+1/72+1/90+1/110+1/132+1/156
Giải thích
a)A=17−113=691.
b)B=13−127=827c)C= 14 43.7+47.11+411.15+415.19+419.23+423.27=227d)D=151−131=631
a)A=17−113=691.
b)B=13−127=827c)C= 14 43.7+47.11+411.15+415.19+419.23+423.27=227d)D=151−131=631