`@` `\text {Ans}`
`\downarrow`
`a,`
`2/5 + x = 2/7`
`=> x = 2/7 -2/5`
`=> x= - 4/35`
Vậy, `x=-4/35`
`b,`
`x + 3/5 = -2/5`
`=> x = -2/5 - 3/5`
`=> x=-1`
Vậy, `x=-1`
`c, `
`x - 8/5 = 3/7`
`=> x=3/7 + 8/5`
`=> x=71/35`
Vậy, `x=71/35`
`d,`
`3/5 - x = 7/3`
`=> x=3/5 - 7/3`
`=> x=-26/15`
Vậy, `x=-26/15`
a) \(\dfrac{2}{5}+x=\dfrac{2}{7}\)
\(\Rightarrow x=\dfrac{2}{7}-\dfrac{2}{5}\)
\(\Rightarrow x=-\dfrac{4}{35}\)
b) \(x+\dfrac{3}{5}=-\dfrac{2}{5}\)
\(\Rightarrow x=-\dfrac{2}{5}-\dfrac{3}{5}\)
\(\Rightarrow x=-1\)
c) \(x-\dfrac{8}{5}=\dfrac{3}{7}\)
\(\Rightarrow x=\dfrac{3}{7}+\dfrac{8}{5}\)
\(\Rightarrow x=\dfrac{71}{35}\)
d) \(\dfrac{3}{5}-x=\dfrac{7}{3}\)
\(\Rightarrow x=\dfrac{3}{5}-\dfrac{7}{3}\)
\(\Rightarrow x=-\dfrac{26}{15}\)
\(a,\dfrac{2}{5}+x=\dfrac{2}{7}\\ x=\dfrac{2}{7}-\dfrac{2}{5}\\ x=\dfrac{10}{35}-\dfrac{14}{35}\\ x=\dfrac{4}{35}\\ b,x+\dfrac{3}{5}=\dfrac{-2}{5}\\ x=\dfrac{-2}{5}-\dfrac{3}{5}\\ x=\dfrac{-5}{5}\\ x=-1\\ c,x-\dfrac{8}{5}=\dfrac{3}{7}\\ x=\dfrac{3}{7}+\dfrac{8}{5}\\ x=\dfrac{15}{35}+\dfrac{56}{35}\\ x=\dfrac{71}{35}\\ d,\dfrac{3}{5}-x=\dfrac{7}{3}\\ x=\dfrac{3}{5}-\dfrac{7}{3}\\ x=\dfrac{9}{15}-\dfrac{35}{15}\\ x=\dfrac{-26}{15}\)