\(\left|x-0,8\right|+\left(x^2-\dfrac{4}{5}x\right)^2=0\)
Ta có:
\(\left|x-0,8\right|\ge0\forall x\)
\(\left(x^2-\dfrac{4}{5}x\right)^2\ge0\forall x\)
\(\Leftrightarrow\left|x-0,8\right|=0\) hoặc \(\left(x^2-\dfrac{4}{5}x\right)^2=0\)
\(\Rightarrow x-0,8=0\) hoặc \(x^2-\dfrac{4}{5}x=0\)
\(x=0,8\) hoặc \(x=0\) hoặc \(x=\dfrac{4}{5}\)
Vậy \(x\in\left\{0;0,8;\dfrac{4}{5}\right\}\)