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Consider a quadratic equation ax^2 + bx...

Consider a quadratic equation `ax^2 + bx + c = 0` having roots `alpha, beta`. If `4a + 2b + c > 0,a-b+c < 0 and 4a - 2b + C > 0` then `|[alpha] + [beta]|` can be {where [] is greatest integer}

A

`-2`

B

`-1`

C

0

D

1

Text Solution

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The correct Answer is:
To solve the problem step-by-step, we will analyze the given conditions and determine the possible values for the roots of the quadratic equation \( ax^2 + bx + c = 0 \). ### Step 1: Understand the conditions We have the following inequalities: 1. \( 4a + 2b + c > 0 \) 2. \( a - b + c < 0 \) 3. \( 4a - 2b + c > 0 \) These inequalities will help us understand the behavior of the quadratic function \( f(x) = ax^2 + bx + c \). ### Step 2: Evaluate \( f(2) \) From the first condition, we can evaluate: \[ f(2) = a(2^2) + b(2) + c = 4a + 2b + c > 0 \] This means that the value of the quadratic function at \( x = 2 \) is positive. ### Step 3: Evaluate \( f(-1) \) From the second condition, we can evaluate: \[ f(-1) = a(-1^2) + b(-1) + c = a - b + c < 0 \] This means that the value of the quadratic function at \( x = -1 \) is negative. ### Step 4: Evaluate \( f(-2) \) From the third condition, we can evaluate: \[ f(-2) = a(-2^2) + b(-2) + c = 4a - 2b + c > 0 \] This means that the value of the quadratic function at \( x = -2 \) is positive. ### Step 5: Analyze the graph Now, we can analyze the behavior of the quadratic function based on the values we calculated: - \( f(2) > 0 \) indicates that the curve is above the x-axis at \( x = 2 \). - \( f(-1) < 0 \) indicates that the curve is below the x-axis at \( x = -1 \). - \( f(-2) > 0 \) indicates that the curve is above the x-axis at \( x = -2 \). ### Step 6: Determine the roots Since the function is positive at \( x = -2 \) and \( x = 2 \), and negative at \( x = -1 \), we can conclude that: - One root \( \alpha \) is between \( -2 \) and \( -1 \). - The other root \( \beta \) is between \( -1 \) and \( 2 \). ### Step 7: Find the greatest integer values - The greatest integer less than or equal to \( \alpha \) (which lies between \( -2 \) and \( -1 \)) is \( -2 \). - The greatest integer less than or equal to \( \beta \) (which lies between \( -1 \) and \( 2 \)) can be \( -1 \), \( 0 \), or \( 1 \). ### Step 8: Calculate \( |[\alpha] + [\beta]| \) We can summarize the possible cases for \( |[\alpha] + [\beta]| \): 1. If \( [\alpha] = -2 \) and \( [\beta] = -1 \): \[ | -2 + (-1) | = | -3 | = 3 \] 2. If \( [\alpha] = -2 \) and \( [\beta] = 0 \): \[ | -2 + 0 | = | -2 | = 2 \] 3. If \( [\alpha] = -2 \) and \( [\beta] = 1 \): \[ | -2 + 1 | = | -1 | = 1 \] ### Conclusion The possible values for \( |[\alpha] + [\beta]| \) are \( 3, 2, \) and \( 1 \).

To solve the problem step-by-step, we will analyze the given conditions and determine the possible values for the roots of the quadratic equation \( ax^2 + bx + c = 0 \). ### Step 1: Understand the conditions We have the following inequalities: 1. \( 4a + 2b + c > 0 \) 2. \( a - b + c < 0 \) 3. \( 4a - 2b + c > 0 \) ...
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