a: \(\Leftrightarrow x^3-3x^2+3x-1=\dfrac{1}{8}\)
\(\Leftrightarrow\left(x-1\right)^3=\dfrac{1}{8}\)
=>x-1=1/2
hay x=3/2
b: \(\Leftrightarrow x\cdot\dfrac{2}{3}+\dfrac{1}{3}x^2=1-\dfrac{2}{3}x\)
\(\Leftrightarrow x^2+2x=3-2x\)
\(\Leftrightarrow x^2+4x-3=0\)
\(\Leftrightarrow\left(x+2\right)^2=7\)
hay \(x\in\left\{-\sqrt{7}-2;\sqrt{7}-2\right\}\)