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COMPLEX NUMBERS AND QUADRATIC EQUATIONS — MATHS STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceMATHSCOMPLEX NUMBERS AND QUADRATIC EQUATIONS2 Marks
Question
Solve $- x^2 + x - 2 = 0$
✓

Answer

Given:
$- x^2 + x - 2 = 0$
Comparing the given quadratic equation with $ax^2 + bx + c = 0$ we have
a = -1,b = 1 and c = -2x = ${-b \pm \sqrt{b^2-4ac} \over 2a}$
$\therefore x = \frac{{ - (1) \pm \sqrt {{{(1)}^2} - 4 \times (-1) \times (-2)} }}{{2 \times (-1)}}$ = $ \frac{{-1 \pm \sqrt { 7} i}}{-2}$
Thus $x = \frac{{-1 \pm \sqrt 7 i}}{-2}$

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