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Find the roots of the following equation, if they exist, by applying the quadratic formula: x^2 + x + 2 = 0

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Question

Find the roots of the following equation, if they exist, by applying the quadratic formula:

x2 + x + 2 = 0

Sum
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Solution

Given: x2 + x + 2 = 0

Step-wise calculation:

1. Compare with ax2 + bx + c = 0:

a = 1, b = 1, c = 2

2. Quadratic formula:

`x = (-b ± sqrt(b^2 - 4ac))/(2a)`

3. Compute discriminant:

D = b2 – 4ac

= 12 – 4(1)(2) 

= 1 – 8

= –7

4. Substitute:

`x = (-1 ± sqrt(-7))/2` 

= `(-1 ± isqrt(7))/2`

The equation has no real roots; its two complex conjugate roots are `x = (-1 + isqrt(7))/2` and `x = (-1 - isqrt(7))/2`.

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Chapter 4: Quadratic Equations - EXERCISE 4B [Page 193]

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R.S. Aggarwal Mathematics [English] Class 10
Chapter 4 Quadratic Equations
EXERCISE 4B | Q 16. | Page 193
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