111) Arithmetic progression a1= ? , a3=x+7 ,a7=x+49

Question

111) Arithmetic progression a1= ? , a3=x+7 ,a7=x+49

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Jasmine 7 months 2021-10-15T21:52:42+00:00 1 Answer 0 views 0

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    2021-10-15T21:54:38+00:00

    Answer:

    let common difference of the arithmetic progression is d

    so,a3=a1+2d=x+7

    a7=a1+6d=x+49

    subtracting,

    (a1+2d)-(a1+6d)=(x+7)-(x+49)

    a1+2d-a1-6d=x+7-x-49

    -4d= -42

    d= -42/-4=42/4=21/2

    a1+2d=x+7

    a1=x+7-2d=x+7-2.21/2

    a1=x+7-21=x-14

    a1=x-14

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