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Complex Numbers — Maths STD 11 Science — Question

Maharashtra BoardEnglish MediumSTD 11 ScienceMathsComplex Numbers2 Marks
MCQ
The roots of equation $x^2+x+1=0$ are
  • A
    $\frac{-1 \pm i}{2}$
  • B
    $\frac{1 \pm \sqrt{3} i}{2}$
  • ✓
    $\frac{-1 \pm \sqrt{3} i}{2}$
  • D
    $\frac{-i \pm \sqrt{3}}{2}$
✓

Answer

Correct option: C.
$\frac{-1 \pm \sqrt{3} i}{2}$
(C)
Here, $a=1, b=1$ and $c=1$
$a=1, b=1$ and $c=1$
$\therefore \quad x=\frac{-1 \pm \sqrt{(1)^2-4(1)(1)}}{2(1)}=\frac{-1 \pm \sqrt{1-4}}{2}$
$=\frac{-1 \pm \sqrt{3} i }{2}$

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