4. 2x² - 3 = 0

Решение:
2x² = 3
x² = \(\frac{3}{2}\)
x = \(\pm\)\(\sqrt{\frac{3}{2}}\)
x = \(\pm\) \(\frac{\sqrt{6}}{2}\)
Ответ: x = $$\frac{\sqrt{6}}{2}$$, x = -$$\frac{\sqrt{6}}{2}$$