2 câu trả lời
`2/3x + 5/7=3/10`
`2/3x =3/10- 5/7`
`2/3x =21/70- 50/70`
`2/3x =- 29/70`
`x =- 29/70:2/3`
`x =- 87/140`
Vậy `x =- 87/140`.
$\frac{2}{3}$x+$\frac{5}{7}$=$\frac{3}{10}$
=>$\frac{2}{3}$x=$\frac{3}{10}$-$\frac{5}{7}$
=>$\frac{2}{3}$x=$\frac{-29}{70}$
=> x=$\frac{-29}{70}$:$\frac{2}{3}$
=>x=$\frac{-87}{140}$
