Question

tính bằng cách thuận tiện b 3/7 x 9/5 - 3/7 x 4/5

Answer 1

\(=\dfrac{3}{7}.\left(\dfrac{9}{5}-\dfrac{4}{5}\right)=\dfrac{3}{7}.\left(\dfrac{5}{5}\right)=\dfrac{3}{7}.1=\dfrac{3}{7}\)

Answer 2

`3/7 xx 9/5 - 3/7 xx 4/5`

`=3/7 xx ( 9/5 - 4/5)`

`=3/7 xx ((9-4)/5)`

`=3/7 xx 5/5`

`=3/7 xx 1`

`=3/7`

Answer 3

\(\dfrac{3}{7}\times\left(\dfrac{9}{5}-\dfrac{4}{5}\right)=\dfrac{3}{7}\times\dfrac{5}{5}=\dfrac{3}{7}\)

Answer 4

\(\dfrac{3}{7}\times\dfrac{9}{5}-\dfrac{3}{7}\times\dfrac{4}{5}\)

\(=\dfrac{3}{7}\left(\dfrac{9}{5}-\dfrac{4}{5}\right)\)

\(=\dfrac{3}{7}\times1=\dfrac{3}{7}\)

Answer 5

b) \(=\dfrac{3}{7}x\left(\dfrac{9}{5}-\dfrac{4}{5}\right)=\dfrac{3}{7}x\dfrac{5}{5}=\dfrac{3}{7}x1=\dfrac{3}{7}\)

Answer 6

`3/7 xx 9/5 - 3/7xx4/5`

`=3/7xx(9/5-4/5)`

`=3/7xx5/5`

`=3/7xx1=3/7`