Question

Giúp mình

Answer 1

a, \(x-\dfrac{2}{5}=\dfrac{5}{7}\)

\(x=\dfrac{5}{7}+\dfrac{2}{5}\)

\(x=\dfrac{39}{35}\)

Vậy ..............

b, \(-x-\dfrac{2}{3}=\dfrac{-6}{7}\)

\(-x=\dfrac{-6}{7}+\dfrac{2}{3}\)

\(-x=\dfrac{-4}{21}\)

\(\Leftrightarrow x=\dfrac{4}{21}\)

Vậy ...

Answer 2

-x=- \(\dfrac{6}{7}\)+\(\dfrac{2}{3}\)

-x =- \(\dfrac{4}{21}\)

=> x = \(\dfrac{4}{21}\)