Question

If one root of the equation $2x^2+bx+2=0$ is $-2$, then the other root is:

• A. $1$
• B. $\frac{1}{2}$
• C. $2$
• D. $\frac{-1}{2}$

Answer 1

The correct option is D $\frac{-1}{2}$

The given equation is $2x^2+bx+2=0$.
If the coefficients $a$ and $c$ are equal in a quadratic equation $a{x}^2+bx+c=0$, then the roots are reciprocals of each other.
Here the coefficient of $x^2$ and the constant term are equal.
$\therefore$ the roots are reciprocals of each other.
$\Rightarrow \frac{-1}{2}$ is the other root.