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If alpha and beta are the zeroes of the...

If `alpha and beta` are the zeroes of the quadratic equation `x^2 – 12x + 32 = 0`, then a quadratic equation whose zeroes are `1/(2alpha+beta)and 1/(2beta+alpha) ` is

A

`320x^2 + 36x + 1 = 0`

B

`320x^2 – 36x – 1 = 0`

C

`320x^2 - 36x + 1 = 0`

D

`320x^2 + 36x - 1 = 0`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will first find the roots (zeroes) of the given quadratic equation and then derive the new quadratic equation based on the transformed roots. ### Step 1: Find the roots of the quadratic equation The given quadratic equation is: \[ x^2 - 12x + 32 = 0 \] We can use the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1, b = -12, c = 32 \). Calculating the discriminant: \[ b^2 - 4ac = (-12)^2 - 4 \cdot 1 \cdot 32 = 144 - 128 = 16 \] Now, substituting the values into the quadratic formula: \[ x = \frac{12 \pm \sqrt{16}}{2 \cdot 1} = \frac{12 \pm 4}{2} \] Calculating the two roots: 1. \( x_1 = \frac{12 + 4}{2} = \frac{16}{2} = 8 \) 2. \( x_2 = \frac{12 - 4}{2} = \frac{8}{2} = 4 \) Thus, the roots (zeroes) are: \[ \alpha = 8, \quad \beta = 4 \] ### Step 2: Calculate the new roots We need to find the new roots: 1. \( \frac{1}{2\alpha + \beta} \) 2. \( \frac{1}{2\beta + \alpha} \) Calculating each: 1. For \( \frac{1}{2\alpha + \beta} \): \[ 2\alpha + \beta = 2 \cdot 8 + 4 = 16 + 4 = 20 \] \[ \text{So, } \frac{1}{2\alpha + \beta} = \frac{1}{20} \] 2. For \( \frac{1}{2\beta + \alpha} \): \[ 2\beta + \alpha = 2 \cdot 4 + 8 = 8 + 8 = 16 \] \[ \text{So, } \frac{1}{2\beta + \alpha} = \frac{1}{16} \] ### Step 3: Form the new quadratic equation Let the new roots be \( p = \frac{1}{20} \) and \( q = \frac{1}{16} \). The sum of the roots \( p + q \): \[ p + q = \frac{1}{20} + \frac{1}{16} \] Finding a common denominator (LCM of 20 and 16 is 80): \[ p + q = \frac{4}{80} + \frac{5}{80} = \frac{9}{80} \] The product of the roots \( p \cdot q \): \[ p \cdot q = \frac{1}{20} \cdot \frac{1}{16} = \frac{1}{320} \] Using the sum and product of the roots, we can write the quadratic equation: \[ x^2 - (p + q)x + (p \cdot q) = 0 \] Substituting the values: \[ x^2 - \frac{9}{80}x + \frac{1}{320} = 0 \] ### Step 4: Clear the fractions To eliminate the fractions, multiply the entire equation by 320 (the least common multiple of the denominators): \[ 320x^2 - 36x + 1 = 0 \] ### Final Answer The quadratic equation whose zeroes are \( \frac{1}{2\alpha + \beta} \) and \( \frac{1}{2\beta + \alpha} \) is: \[ 320x^2 - 36x + 1 = 0 \]
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