Question

If the discriminant of the quadratic equation 4x² + px + 25 = 0; is 0, then find the value of p. Given $p>0.$

• A. 10
• B. 20
• C. 30
• D. -20

Answer 1

The correct option is B

20

Standard form of a quadratic equation is $a{x}^2+bx+c=0.$

By comapring the equation $4x^2+px+25=0$ with standard form, we get

$a=4,b=p$ and $c=25.$

Discriminant, D = $b^2-4\times a\times c$

$\Rightarrow$ $p^2-4\times 4\times 25=0$

$\Rightarrow$ $p^2-400=0$

$\Rightarrow p=20,–20$

Since, its given $p>0$

$p=20$