Question:
If the roots of the equation $a x^{2}+b x+c=0$ are equal, then then $c=?$
(a) $\frac{-b}{2 a}$
(b) $\frac{b}{2 a}$
(c) $\frac{-b^{2}}{4 a}$
(d) $\frac{b^{2}}{4 a}$
Solution:
(d) $\frac{b^{2}}{4 a}$
It is given that the roots of the equation $\left(a x^{2}+b x+c=0\right)$ are equal.
$\therefore\left(b^{2}-4 a c\right)=0$
$\Rightarrow b^{2}=4 a c$
$\Rightarrow c=\frac{b^{2}}{4 a}$
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.