2/3.5 + 2/5.7 + 2/7.9 +2/9.10 đề để yên ko đổi ạ 30/10/2021 Bởi Josephine 2/3.5 + 2/5.7 + 2/7.9 +2/9.10 đề để yên ko đổi ạ
$\frac{2}{3}×5+\frac{2}{5}×7+\frac{2}{7}×9+\frac{2}{9}×10$ $=\frac{10}{3}+\frac{14}{5}+\frac{18}{7}+\frac{20}{9}$ $=\frac{92}{15}+\frac{18}{7}+\frac{20}{9}$ $=\frac{914}{105}+\frac{20}{9}$ $=\frac{3442}{315}$ Bình luận
`2/3.5 + 2/5.7 + 2/7.9 +2/9.10` `=1/3-1/5 + 1/5-1/7 + 1/7-1/9 +1/9-1/10` `=1/3-1/10` `=7/30` Bình luận
$\frac{2}{3}×5+\frac{2}{5}×7+\frac{2}{7}×9+\frac{2}{9}×10$
$=\frac{10}{3}+\frac{14}{5}+\frac{18}{7}+\frac{20}{9}$
$=\frac{92}{15}+\frac{18}{7}+\frac{20}{9}$
$=\frac{914}{105}+\frac{20}{9}$
$=\frac{3442}{315}$
`2/3.5 + 2/5.7 + 2/7.9 +2/9.10`
`=1/3-1/5 + 1/5-1/7 + 1/7-1/9 +1/9-1/10`
`=1/3-1/10`
`=7/30`