VT

2/5+3/7-(4/9+3/5-13/35)+1/5

NT
26 tháng 8 2024 lúc 20:31

\(\dfrac{2}{5}+\dfrac{3}{7}-\left(\dfrac{4}{9}+\dfrac{3}{5}-\dfrac{13}{35}\right)+\dfrac{1}{5}\)

\(=\dfrac{3}{5}+\dfrac{3}{7}-\dfrac{4}{9}-\dfrac{3}{5}+\dfrac{13}{35}\)

\(=\dfrac{3}{7}+\dfrac{13}{35}-\dfrac{4}{9}\)

\(=\dfrac{28}{35}-\dfrac{4}{9}=\dfrac{4}{5}-\dfrac{4}{9}=\dfrac{36-20}{45}=\dfrac{16}{45}\)

Bình luận (0)
H24
26 tháng 8 2024 lúc 20:33

`2/5 + 3/7 - (4/9 + 3/5 - 13/35) + 1/5`

` = 2/5 + 3/7 - 4/9 - 3/5 + 13/35 + 1/5`

` = (2/5 -3/5 + 1/5) + (3/7 + 13/35) - 4/9`

` = 0 + 28/35 - 4/9`

` = 28/35 - 4/9`

` = 4/5 - 4/9`

` = 36/45 - 20/45`

` = 16/45`

Bình luận (0)