Question

tìm x biết : 3x - ( 2/5 + x ) = 0, 4

 

Answer 1

\(3x-\left(\dfrac{2}{5}+x\right)=0,4\)

\(3x-\dfrac{2}{5}-x=0,4\)

\(2x-\dfrac{2}{5}=\dfrac{2}{5}\)

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

\(2x=\dfrac{4}{5}\)

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

Answer 2

Ta có: \(3x-\left(x+\dfrac{2}{5}\right)=\dfrac{2}{5}\)

\(\Leftrightarrow2x-\dfrac{2}{5}=\dfrac{2}{5}\)

\(\Leftrightarrow2x=\dfrac{4}{5}\)

hay \(x=\dfrac{2}{5}\)