[tex] 18n^2-50=0\ \ \ |+50\\\\18n^2=50\ \ \ |:18\\\\n^2=\dfrac{50}{18}\\\\n^2=\dfrac{50:2}{18:2}\\\\n^2=\dfrac{25}{9}\to n=\pm\sqrt{\dfrac{25}{9}}\\\\n=\pm\dfrac{\sqrt{25}}{\sqrt{9}}\\\\\boxed{n=-\dfrac{5}{3}\ \vee\ n=\dfrac{5}{3}} [/tex]
[tex]Used:\\\sqrt{\dfrac{a}{b}}=\dfrac{\sqrt{a}}{\sqrt{b}}[/tex]
