\[\boxed{\text{302\ (302).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[y = x^{2} - 3\]
\[x^{2} - 3 = 0\]
\[x^{2} = 3\]
\[x = \pm \sqrt{3}.\]
\[\textbf{а)}\ y > 0\ \ при\ \ \]
\[x \in \left( - \infty;\ - \sqrt{3} \right) \cup \left( \sqrt{3}; + \infty \right);\]
\[\textbf{б)}\ y < 0\ \ \ при\ \ x \in \left( - \sqrt{3};\sqrt{3} \right).\]