[tex]y^{2} = 10^{2}+6^{2}\\\\y^{2} = 100 + 36\\\\y^{2} = 136\\\\y^{2}-136 = 0\\\\(y+\sqrt{136})(y-\sqrt{136}) = 0\\\\(y + \sqrt{4\cdot34})(y-\sqrt{4\cdot34}) = 0\\\\(y+2\sqrt{34})(y-2\sqrt{34}) = 0\\\\y + 2\sqrt{34} = 0 \ \ \vee \ \ y-2\sqrt{34}} = 0\\\\\underline{y = -2\sqrt{34} \ \ \vee \ \ y = 2\sqrt{34}}\\\\y \in \{-2\sqrt{34}, 2\sqrt{34}\}[/tex]
