2x² - 9 = 0
2x² = 9
x² = 9/2
x² = ± √9/2
x² = ± 3√2/2
S = {3√2/2, -3√2/2}
[tex]S = ( \frac{3 \sqrt{2} }{2} ,- \frac{3 \sqrt{2} }{2} )[/tex]
