Question

[Nguyễn Thị Hà Anh]

làm giúp mình nha, gấp lắm rồi

Answer 1

[Phía sau một cô gái]

\(3\dfrac{2}{7}-\dfrac{2}{5}+\dfrac{5}{7}-\dfrac{3}{5}\)

\(=\dfrac{23}{7}-\dfrac{2}{5}+\dfrac{5}{7}-\dfrac{3}{5}\)

\(=\left[\dfrac{23}{7}+\dfrac{5}{7}\right]+\left[\left(\dfrac{-2}{5}\right)+\left(\dfrac{-3}{5}\right)\right]\)

\(=4+\left(-1\right)\)

\(=3\)

Answer 2

[Nguyễn Lê Phước Thịnh]

\(=3+\dfrac{2}{7}+\dfrac{5}{7}-\dfrac{2}{5}-\dfrac{3}{5}=3+1-1=3\)