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CLASS_11_MATHS_SOLUTIONS_NCERT

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Class XI Chapter 5 – Complex Numbers and Quadratic Equations Maths<br />

______________________________________________________________________________<br />

Exercise 5.3<br />

Question 1:<br />

Solve the equation<br />

Solution 1:<br />

2<br />

x <br />

30<br />

The given quadratic equation is<br />

2<br />

x <br />

On comparing the given equation with<br />

We obtain<br />

a 1, b 0, and c 3<br />

3 0<br />

2<br />

ax bx c<br />

0,<br />

Therefore, the discriminant of the given equation is<br />

2 2<br />

D b 4ac<br />

0 413 12<br />

Therefore, the required solutions are<br />

b D 12 12i<br />

1 i<br />

2a<br />

21 2<br />

<br />

2 3i<br />

<br />

2<br />

3i<br />

Question 2:<br />

Solve the equation<br />

Solution 2:<br />

2<br />

2x<br />

x1 0<br />

The given quadratic equation is<br />

On comparing the given equation with<br />

We obtain<br />

and<br />

a2, b1<br />

c 1<br />

2<br />

2x<br />

x1 0<br />

2<br />

ax bx c<br />

0<br />

Therefore, the discriminant of the given equation is<br />

2 2<br />

D b 4ac<br />

1 4 21 18 7<br />

Therefore, the required solutions are<br />

b D 1 7 1<br />

7i<br />

1<br />

i<br />

2a<br />

2<br />

2 4<br />

<br />

,<br />

Question 3:<br />

Solve the equation<br />

Solution 3:<br />

x<br />

2<br />

3x 9 0<br />

2<br />

The given quadratic equation is x 3x 9 0

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