If -5 is the root of a quadratic equation 2x^2+px – 15=0 and the quadratic equation p(x^2+x)+k=0 has equal roots. Find k​

Question

If -5 is the root of a quadratic equation 2x^2+px – 15=0 and the quadratic equation p(x^2+x)+k=0 has equal roots. Find k​

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Margaret 3 weeks 2021-10-05T07:09:35+00:00 1 Answer 0 views 0

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    2021-10-05T07:11:12+00:00

    Answer:

    50-5p-15=0

    5p=50-15

    5p=35

    p=7

    therefore .

    p(x^2+x)+k=0

    7x^2 +7x+k=0

    now comparing the equations with general equations we get

    a1=2,a2=7,b1=7,b2=7,c1=-15,c2=k

    as roots are equal therefore(a1÷ a2)=(b1÷b2)=(c1÷c2)

    therefore

    2÷7=15÷k

    2k=105

    k=52.5

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