\[x² + 2x - 3 = 0\]
\[x = 0 \Longrightarrow 0^{2} + 2 \cdot 0 - 3 = 0 \Longrightarrow\]
\[\Longrightarrow - 3 \neq 0 \Longrightarrow не\ корень\]
\[x = 0,5 \Longrightarrow \frac{1}{4} + 2 \cdot \frac{1}{2} - 3 = 0 \Longrightarrow\]
\[\Longrightarrow \frac{1}{4} - 2 \neq 0 \Longrightarrow не\ корень\]
\[x = 1 \Longrightarrow 1 + 2 - 3 = 0 \Longrightarrow\]
\[\Longrightarrow 0 = 0 \Longrightarrow \ корень\]
\[x = - \frac{1}{6} \Longrightarrow \frac{1}{36} - \frac{1}{3} - 3 = 0 \Longrightarrow\]
\[\Longrightarrow \frac{1 - 12}{36} - 3 \neq 0 \Longrightarrow не\ корень\]
\[x = - 3 \Longrightarrow 9 - 6 - 3 = 0 \Longrightarrow\]
\[\Longrightarrow 0 = 0 \Longrightarrow \ корень.\]