Mathematics

If the 2nd and 5th term of a g.p are -6 and 48 respectively.Find the sum of the first four terms

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  1. https://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
    a+d = -6
    a+ 4d = 48
    ---------------
    -3 d = -54
    d = 18
    a + 18 = -6
    a = -24
    so
    -24 , -6 , 12 , 30 , then 48 is next

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    Damon
  2. Whoops sorry, thought ap but you said gp
    https://www.mathsisfun.com/algebra/sequences-sums-geometric.html
    a , a r , a r^2 , a r^3 , a r^4
    a r = -6
    a r^4 = 48
    so
    -6 r^3 = 48
    r^3 = -8
    r = -2
    then a = 3
    continue as before

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    Damon

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