Question

thực hiện phép tính

\(\dfrac{\dfrac{2}{3}-}{\dfrac{8}{3}-}\dfrac{\dfrac{2}{5}+}{\dfrac{8}{5}+}\dfrac{\dfrac{2}{7}}{\dfrac{8}{7}}\)

Answer 1

\(\dfrac{\dfrac{2}{3}-\dfrac{2}{5}+\dfrac{2}{7}}{\dfrac{8}{3}-\dfrac{8}{5}+\dfrac{8}{7}}=\dfrac{2\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{7}\right)}{8\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{7}\right)}\\ =\dfrac{2}{8}=\dfrac{1}{4}\)

Answer 2

2/3 - 2/5 + 2/7

= 70/105 - 42/105 + 20/105

= (70 - 42 + 20) / 105

= 48 / 105

= 16/35

 

8/3 - 8/5 + 8/7

= 280/105 - 168 / 105 + 120/105

= ( 280 - 168 + 120 ) / 105

= 232/105

 

 

Answer 3

2/3 - 2/5 + 2/7

= 70/105 - 42/105 + 30/105

= (70 - 42 + 30) / 105

= 58 / 105