Question

What will be the value(s) of 'p' if the quadratic equation $2x^2+px+2=0$ has two equal real roots?

• A. 4 or -4
• B. 2 or -2
• C. 3 or -3
• D. 1 or -1

Answer 1

The correct option is A 4 or -4

Since the equation $2x^2+px+2=0$ has 2 equal real roots, its discriminant will be zero.

On comparing $2x^2+px+2=0$ with the standard form of quadratic equation $a{x}^2+bx+c=0$, we get,
a =2, b =p and c = 2.

$\Rightarrow b^2-4ac=0\Rightarrow p^2-4\times 2\times 2=0$
$\Rightarrow p^2-16=0$
$\Rightarrow p^2=16$
$\Rightarrow p=\pm 4$