Question

\(\left(z-\dfrac{2}{15}\right)^3=\dfrac{8}{125}\)

Answer 1

  \(\left(z-\dfrac{2}{15}\right)^3=\dfrac{8}{125}\)

  \(\left(z-\dfrac{2}{15}\right)^3=\left(\dfrac{2}{5}\right)^3\)

\(\Rightarrow z-\dfrac{2}{15}=\dfrac{2}{5}\)

     \(z=\dfrac{2}{5}+\dfrac{2}{15}\)

     \(z=\dfrac{8}{15}\)

Answer 2

Ta có: \(\left(z-\dfrac{2}{15}\right)^3=\dfrac{8}{125}\)

\(\Leftrightarrow\left(z-\dfrac{2}{15}\right)^3=\left(\dfrac{2}{5}\right)^3\)

\(\Leftrightarrow z-\dfrac{2}{15}=\dfrac{2}{5}\)

\(\Leftrightarrow z=\dfrac{2}{5}+\dfrac{2}{15}=\dfrac{6}{15}+\dfrac{2}{15}\)

hay \(z=\dfrac{8}{15}\)

Vậy: \(z=\dfrac{8}{15}\)