MCQ
If $a x^2+b x+c=0$ has equal roots, then c is equal to
- A$\frac{b^2}{2 a}$
- ✓$\frac{b^2}{4 a}$
- C$\frac{-b^2}{4 a}$
- D$-\frac{b^2}{2 a}$
✓
Answer
Correct option: B.
$\frac{b^2}{4 a}$
If $a x^2+b x+c=0$ has equal roots, then
$b^2-4 a c=0$
$\Rightarrow 4 a c=b^2$
$\Rightarrow c=\frac{b^2}{4 a}$
$b^2-4 a c=0$
$\Rightarrow 4 a c=b^2$
$\Rightarrow c=\frac{b^2}{4 a}$
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