Question

The roots of the equation $2x^2+4x+5$ = 0 are .

• A. real & equal
• B. real & unequal
• C. not real

Answer 1

The correct option is C not real

The nature of the roots of a quadratic polynomial depends upon its discriminant.
The discriminant of a quadratic equation $a{x}^2+bx+c=0,$ where $a,b$ and $c$ are constants, is given by $b^2-4ac.$
$\therefore$ The discriminant of the equation given is
$D=b^2-4ac=4^2-4\left(2\right)\left(5\right)=-24$
Since $D<0,$ the roots of the equation are not real.