Question

$- 2x {}^{2} - x + 28 = 0$
​

Answer 1

$x1 = - 4 \\ x2 = 3.5$

Explicación paso a paso:

$\bold{ tema \: ecuaciones \: de \: segundo \: grado(metodo \: de \: \: formula \: general}$

${ - 2x}^{2} - x + 28 = 0 \\ {a}^{2} - bx + c = 0 \\ \\ x = \frac{b + - \sqrt{ {b}^{2} - 4ac } }{2a} \\ \\ a = - 2 \\ b = - 1 \\ c = 28$

$x = \frac{ - ( - 1) + - \sqrt{ {( - 1)}^{2} - 4( - 2)(28)} }{2( - 2)} \\ \\ x = \frac{1 + - \sqrt{1 - - 224} }{ - 4} = \frac{1 + - \sqrt{225} }{ - 4} = \frac{1 + - 15}{ - 4}$

$x1 = \frac{1 + 15}{ - 4} = \frac{16}{ - 4} = - 4 \\ \\ x2 = \frac{1 - 15}{ - 4} = \frac{ - 14}{ - 4} = \frac{7}{2} = 3.5$

$x1 = - 4 \\ x2 = 3.5$