2 consecutive odd integers such that their product is 15 more than 3 times their sum

Discussion in 'Calculator Requests' started by math_celebrity, Nov 18, 2018.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    2 consecutive odd integers such that their product is 15 more than 3 times their sum.

    Let the first integer be n. The next odd, consecutive integer is n + 2.

    We are given the product is 15 more than 3 times their sum:
    n(n + 2) = 3(n + n + 2) + 15

    Simplify each side:
    n^2 + 2n = 6n + 6 + 15
    n^2 + 2n = 6n + 21

    Subtract 6n from each side:
    n^2 - 4n - 21 = 0

    Type this problem into our search engine, and we get:
    n = (-3, 7)

    If we use -3, then the next consecutive odd integer is -3 + 2 = -1. So we have (-3, -1)
    If we use 7, then the next consecutive odd integer is 7 + 2 = 9. So we have (7, 9)
     

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