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The integral value of m for which the qu...

The integral value of m for which the quadratic equation `(2m-3)x^2-4x+2m-3=0` has both the roots negative is given by

A

1

B

2

C

3

D

5

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To find the integral value of \( m \) for which the quadratic equation \( (2m-3)x^2 - 4x + (2m-3) = 0 \) has both roots negative, we will follow these steps: ### Step 1: Identify the coefficients The given quadratic equation can be expressed in the standard form \( ax^2 + bx + c = 0 \) where: - \( a = 2m - 3 \) - \( b = -4 \) - \( c = 2m - 3 \) ### Step 2: Conditions for negative roots For the quadratic equation to have both roots negative, we need to satisfy the following conditions: 1. The discriminant \( D \) must be greater than 0: \( D > 0 \) 2. The sum of the roots \( \alpha + \beta < 0 \) 3. The product of the roots \( \alpha \beta > 0 \) ### Step 3: Calculate the discriminant The discriminant \( D \) is given by: \[ D = b^2 - 4ac = (-4)^2 - 4(2m - 3)(2m - 3) \] \[ D = 16 - 4(2m - 3)^2 \] For \( D > 0 \): \[ 16 - 4(2m - 3)^2 > 0 \] Dividing through by 4: \[ 4 - (2m - 3)^2 > 0 \] This can be rewritten as: \[ (2m - 3)^2 < 4 \] Taking the square root: \[ -2 < 2m - 3 < 2 \] Adding 3 to all parts: \[ 1 < 2m < 5 \] Dividing by 2: \[ \frac{1}{2} < m < \frac{5}{2} \] ### Step 4: Sum of the roots The sum of the roots \( \alpha + \beta \) is given by: \[ \alpha + \beta = -\frac{b}{a} = \frac{4}{2m - 3} \] For \( \alpha + \beta < 0 \): \[ \frac{4}{2m - 3} < 0 \] This implies: \[ 2m - 3 < 0 \implies m < \frac{3}{2} \] ### Step 5: Product of the roots The product of the roots \( \alpha \beta \) is given by: \[ \alpha \beta = \frac{c}{a} = \frac{2m - 3}{2m - 3} \] Since \( \alpha \beta > 0 \), and \( 2m - 3 \) must be positive: \[ 2m - 3 > 0 \implies m > \frac{3}{2} \] ### Step 6: Combine conditions Now we have three conditions: 1. \( \frac{1}{2} < m < \frac{5}{2} \) 2. \( m < \frac{3}{2} \) 3. \( m > \frac{3}{2} \) The only feasible condition is: \[ \frac{1}{2} < m < \frac{3}{2} \] ### Step 7: Integral values of \( m \) The integral values of \( m \) in the interval \( \left(\frac{1}{2}, \frac{3}{2}\right) \) is only: \[ m = 1 \] ### Conclusion Thus, the integral value of \( m \) for which the quadratic equation has both roots negative is: \[ \boxed{1} \]
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