Question

Using the quadratic formula to solve 2x² - 4x-7, what are the values of x?

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O 18 -√101
28/101
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012-√51

Answer 1

`~~~~~~~~~~~~\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√(2)}{4}\implies x=\cfrac{2\pm 3√(2)}{2}\implies x= \begin{cases} (2\pm 3√(2))/(2)\\\\ -(2\pm 3√(2))/(2) \end{cases}`