[tex]~~~~~~~~~~~~\textit{quadratic formula} \\\\ y=\stackrel{\stackrel{a}{\downarrow }}{2}x^2\stackrel{\stackrel{b}{\downarrow }}{-4}x\stackrel{\stackrel{c}{\downarrow }}{-7} \qquad \qquad x= \cfrac{ - b \pm \sqrt { b^2 -4 a c}}{2 a} \\\\\\ x= \cfrac{ - (-4) \pm \sqrt { (-4)^2 -4(2)(-7)}}{2(2)} \implies x= \cfrac{ 4 \pm \sqrt { 16 +56}}{ 4 } \\\\\\ x=\cfrac{4\pm 6\sqrt{2}}{4}\implies x=\cfrac{2\pm 3\sqrt{2}}{2}\implies x= \begin{cases} \frac{2\pm 3\sqrt{2}}{2}\\\\ -\frac{2\pm 3\sqrt{2}}{2} \end{cases}[/tex]
