Question

Using the quadratic formula, solve
0 = 2x² - 8x +5
Give each of your answers to 2 d.p.

Answer 1

`~~~~~~~~~~~~\textit{quadratic formula} \\\\ 0=\stackrel{\stackrel{\textit{\small a}}{\downarrow }}{2}x^2\stackrel{\stackrel{\textit{\small b}}{\downarrow }}{-8}x\stackrel{\stackrel{\textit{\small c}}{\downarrow }}{+5} \qquad \qquad x= \cfrac{ - b \pm \sqrt { b^2 -4 a c}}{2 a}`

`x= \cfrac{ - (-8) \pm \sqrt { (-8)^2 -4(2)(5)}}{2(2)} \implies x = \cfrac{ 8 \pm \sqrt { 64 -40}}{ 4 } \\\\\\ x= \cfrac{ 8 \pm \sqrt { 24 }}{ 4 }\implies x=\cfrac{ 8 \pm 2\sqrt { 6 }}{ 4 }\implies x=\cfrac{4\pm√(6)}{2}\implies x\approx \begin{cases} 3.22\\ 0.78 \end{cases}`