Rieš v \( \mathbb{R} \) nerovnicu \( 9 x^{2}-6 x+1 \leq 0 \).
\( K=\left\{\frac{1}{3}\right\} \)
\( K=\left\{\frac{1}{2}\right\} \)
\( K=\left\{-\frac{1}{3}\right\} \)
\( K=\left\{0\right\} \)
