4) If roots of a quadratic equation 3y2+ ky+ 12= 0 are real and equal then

find the value of ‘k’.​

Question

4) If roots of a quadratic equation 3y2+ ky+ 12= 0 are real and equal then

find the value of ‘k’.​

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Kennedy 2 months 2021-07-27T14:37:20+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-07-27T14:39:04+00:00

    Answer:

    for \: equal \: roots \: \\ d = 0 \\  {b}^{2}  - 4ac = 0 \\  {k}^{2}  - 4(3)(12) = 0 \\  {k}^{2}  - 144 = 0 \\ k =  \sqrt{144}  = 12 \\ therefore \\ k = 12

    0
    2021-07-27T14:39:12+00:00

    Answer:

    k= 12 or k= -12

    Step-by-step explanation:

    3y^2 + ky + 12 = 0

    a = 3, b = k, c = 12

    b^2 – 4ac = 0                                  _ _ _ _ _( given )

    k^2\\ – 4(3)(12) = 0

    k^2 – (12 x 12) = 0

    ∴        k^2 – 144 = 0

    ∴                 k^2 = 144

    ∴                 k  = \sqrt144                 _ _ _ _ _( taking square roots of both sides)

    ∴                 k  = ±12

    ∴        k = 12               OR               k = -12

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