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    The value of ‘a’ for which one root of the quadratic equation (a² − 5a + 3)x² + (3a − 1)x + 2 = 0 is twice the other, is:
    Question

    The value of ‘a’ for which one root of the quadratic equation (a² − 5a + 3)x² + (3a − 1)x + 2 = 0 is twice the other, is:

    A.

    -2/3

    B.

    1/3

    C.

    - 1/3

    D.

    2/3

    Correct option is D

    Given:

    Equation: (a² − 5a + 3)x² + (3a − 1)x + 2 = 0
    Let roots be α and 2α.

    Concept used:
    For quadratic equation Ax² + Bx + C = 0,
    Sum of roots = −B/A and Product of roots = C/A

    Formula used:
    α + 2α = −B/A and α(2α) = C/A

    Solution:
    A = (a² − 5a + 3), B = (3a − 1), C = 2

    Using sum of roots:

    α+2α=BA=>3α=3a1a25a+3\alpha + 2\alpha = -\frac{B}{A} \Rightarrow 3\alpha = -\frac{3a - 1}{a^2 - 5a + 3}​​

    =>α=3a13(a25a+3)\Rightarrow \alpha = -\frac{3a - 1}{3(a^2 - 5a + 3)}​​

    Using product of roots:
    α2α=CA=>2α2=2a25a+3=>α2=1a25a+3\alpha \cdot 2\alpha = \frac{C}{A} \Rightarrow 2\alpha^2 = \frac{2}{a^2 - 5a + 3} \\\Rightarrow \alpha^2 = \frac{1}{a^2 - 5a + 3}​​

    Substitute into 

    (3a13(a25a+3))2=1a25a+3=>(3a1)29(a25a+3)2=1a25a+3\left( \frac{3a - 1}{3(a^2 - 5a + 3)} \right)^2 = \frac{1}{a^2 - 5a + 3} \\\Rightarrow \frac{(3a - 1)^2}{9(a^2 - 5a + 3)^2} = \frac{1}{a^2 - 5a + 3}​​

    Simplify:
    (3a − 1)² = 9(a² − 5a + 3)
    => 9a² − 6a + 1 = 9a² − 45a + 27
    => −6a + 1 = −45a + 27
    => 39a = 26
    =>a=2639=23\Rightarrow a = \frac{26}{39} = \frac{2}{3}​​

    Correct answer is (d) 2/3.

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