Question

Solve following equation:
$-x^2+x-2=0$

• A. $\frac{1\pm \sqrt{7}i}{2}$
• B. $\frac{-1\pm \sqrt{7}i}{2}$
• C. $\frac{2\pm \sqrt{7}i}{2}$
• D. $\frac{-2\pm \sqrt{7}i}{2}$

Answer 1

The correct option is A $\frac{1\pm \sqrt{7}i}{2}$

The given equation is,

$-x^2+x-2=0$

The roots of the quadratic equation $A{x}^2+Bx+C=0$ are

$x=\frac{-B\pm \sqrt{B^2-4AC}}{2A}$

for the given equation, $B^2-4AC=(1{)}^2-4(-1\left)\right(-2)=-7$

So,

$x=\frac{-1\pm \sqrt{-7}}{-2}$

$x=\frac{1\pm \sqrt{7}i}{2}$