[tex]\displaystyle\bf\\x^{2} < 4\\\\x^{2} -4 < 0\\\\\Big(x-2\Big)\Big\cdot\Big(x+2\Big) < 0\\\\\\+ + + + + (-2) - - - - - (2) + + + + +[/tex]

                      /////////////////

[tex]\displaystyle\bf\\x\in \Big(-2 \ \ ; \ \ 2\Big)[/tex]