Question:
For what values of $p$ are the roots of the equation $4 x^{2}+p x+3=0$ real and equal?
Solution:
The given equation is $4 x^{2}+p x+3=0$.
This is of the form $a x^{2}+b x+c=0$, where $a=4, b=p$ and $c=3$.
$\therefore D=b^{2}-4 a c=p^{2}-4 \times 4 \times 3=p^{2}-48$
The given equation will have real and equal roots if D = 0.
$\therefore p^{2}-48=0$
$\Rightarrow p^{2}=48$
$\Rightarrow p=\pm \sqrt{48}=\pm 4 \sqrt{3}$
Hence, $4 \sqrt{3}$ and $-4 \sqrt{3}$ are the required values of $p$.