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Solve this for x: (16-x^2)^3/2 = 40

  1. Apr 22, 2004 #1
    hi,
    im trying to solve this for x:

    (16-x^2)^3/2 = 40

    ive simplified it by taking the square root, so i get:

    sqrt(16-x^2)^3) = 40

    now i square both sides and i get:

    (16-x^2)^3 = 1600 (Not sure if this is right)

    im not sure what to do next. i think i can take the cube root of both sides, but im not sure.
    Can someone please help me.
    thanks
     
  2. jcsd
  3. Apr 22, 2004 #2
    Yes, you take the cube root of both sides. In fact, you could've just raised both sides to the power of 1/(3/2) = 2/3 in the first place, to get 16 - x^2 = 40^(2/3) (which should be easy to solve).
     
  4. Apr 23, 2004 #3

    HallsofIvy

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    Staff Emeritus
    Science Advisor

    By the way, you didn't actually "take the square root" at the beginning: you simply rewrote the "1/2" power as a square root. You could have said "square both sides" initially.
     
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