Řeš v \( \mathbb{R} \) rovnici:
\( \large \sqrt {{x^2} + 8} = 2x + 1 \)
\( \large K = \left \{ 2 \right \} \)
\( \large K = \left \{ 1 \right \} \)
\( \large K = \left \{ 0 \right \} \)
\( \large K = \left \{ -1 \right \} \)