Řeš v ℝ rovnice pomocí vzorečku:
\large x^{2}-6 x + 9 = 0
K = \left\{ {\left. 0 \right\}} \right.
K = \left\{ {\left. 6 \right\}} \right.
K = \left\{ {\left. 3 \right\}} \right.
K = \left\{ {\left. -3 \right\}} \right.