Vyrieš rovnicu \( (x+2)(2 x-1)=0 \) pre \( x \in \mathbb{R}^{+} \).
\( K=\left\{0\right\} \)
\( K=\left\{\frac{1}{2}\right\} \)
\( K=\left\{-\frac{1}{2}\right\} \)
\( K=\left\{2\right\} \)