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How many real roots does the quadratic e...

How many real roots does the quadratic equation `f(x) = x^(2) + 3 |x|+2 = 0` have ?

A

One

B

Two

C

Fore

D

No real root

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The correct Answer is:
To determine how many real roots the quadratic equation \( f(x) = x^2 + 3|x| + 2 = 0 \) has, we need to analyze the equation by considering the behavior of the absolute value function. ### Step-by-Step Solution: 1. **Understand the Absolute Value**: The absolute value function \( |x| \) behaves differently for positive and negative values of \( x \). Therefore, we will consider two cases: - Case 1: \( x \geq 0 \) (where \( |x| = x \)) - Case 2: \( x < 0 \) (where \( |x| = -x \)) 2. **Case 1: \( x \geq 0 \)**: In this case, the equation becomes: \[ f(x) = x^2 + 3x + 2 = 0 \] We can factor this quadratic equation: \[ (x + 1)(x + 2) = 0 \] Setting each factor to zero gives us the roots: \[ x + 1 = 0 \quad \Rightarrow \quad x = -1 \] \[ x + 2 = 0 \quad \Rightarrow \quad x = -2 \] However, since we are in the case where \( x \geq 0 \), these roots \( -1 \) and \( -2 \) are not valid. 3. **Case 2: \( x < 0 \)**: In this case, the equation becomes: \[ f(x) = x^2 - 3x + 2 = 0 \] We can factor this quadratic equation as well: \[ (x - 1)(x - 2) = 0 \] Setting each factor to zero gives us the roots: \[ x - 1 = 0 \quad \Rightarrow \quad x = 1 \] \[ x - 2 = 0 \quad \Rightarrow \quad x = 2 \] However, since we are in the case where \( x < 0 \), these roots \( 1 \) and \( 2 \) are not valid. 4. **Conclusion**: Since both cases yielded roots that are not valid in their respective domains, we conclude that the quadratic equation \( f(x) = x^2 + 3|x| + 2 = 0 \) has no real roots. ### Final Answer: The quadratic equation has **no real roots**.

To determine how many real roots the quadratic equation \( f(x) = x^2 + 3|x| + 2 = 0 \) has, we need to analyze the equation by considering the behavior of the absolute value function. ### Step-by-Step Solution: 1. **Understand the Absolute Value**: The absolute value function \( |x| \) behaves differently for positive and negative values of \( x \). Therefore, we will consider two cases: - Case 1: \( x \geq 0 \) (where \( |x| = x \)) - Case 2: \( x < 0 \) (where \( |x| = -x \)) ...
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NDA PREVIOUS YEARS-POLYNOMIAL,QUADRATIC EQUATION & INEQUALITIES-Math
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