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Homework Help: Simplifying an expression

  1. Apr 5, 2006 #1
    Well here is the beginning of it:

    [-6(-4)^(n-1)] - 9 + [8(-4)^(n-2)] + 12

    This is suppose to simplify to 2(-4)^2 + 3.

    But I have no idea how that 2(-4)^2 was obtained. Could anybody explain how that would work?
     
  2. jcsd
  3. Apr 5, 2006 #2
    i'm going to assume you meant 2(-4)^n not ^2, because otherwise you'd've simplified further, and besides, ^n is the correct answer. do you know how exponentials work and how to factor? thats all they did, and then simplified.

    use these rules:

    X^(a+b) = (X^a)(X^b)
    and by that:
    X^(a+b) + X^(a+c) = X^a(X^b + X^c)
     
  4. Apr 6, 2006 #3

    HallsofIvy

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    Science Advisor

    It also helps to know that 4= 2^2!
     
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