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    How do I solve 2x-54x^-2=0?
    I started with 2x(1-27x-3)=0
    And got 0 and 3.
    But the answer only says three, where did I go wrong?
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    if you test the numbers in the original LHS you will see that the zero cannot work.
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    This question doesn’t even make sense
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    I belive OP's equation is
    2x-54x^{-2}=0
    which he simplified to
    2x(1-27x^{-3})=0
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    (Original post by Janej77)
    How do I solve 2x-54x^-2=0?
    I started with 2x(1-27x-3)=0
    And got 0 and 3.
    But the answer only says three, where did I go wrong?
    Could you rewrite the question? It looks like you've written 2x-54x^{-2}=0
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    (Original post by ManLike007)
    Could you rewrite the question? It looks like you've written 2x-54x^{-2}=0
    2x-54x^(-2)=0
    I factorised to 2x(1-27x^-3)=0
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    2x-54x^-2=0
    2x-54/x^2=0
    multiply both sides by x^2
    2x^3-54=0
    2x^3=54
    Divide both sides by 2
    x^3=27
    so x=3
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    (Original post by Janej77)
    2x-54x^(-2)=0
    I factorised to 2x(1-27x^-3)=0
    Your solutions are correct to obtain the values 0 and 3.

    However, the answer cannot be 0 and here's why (I think):

    Substituting in x=0

    2(0)-\frac{54}{0^{2}}=0 doesn't work because \frac{54}{0} is undefined which affects the rest of the equation. Divide any number by zero you'll get an error on your calculator
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    (Original post by Novelister)
    2x-54x^-2=0
    2x-54/x^2=0
    multiply both sides by x^2
    2x^3-54=0
    2x^3=54
    Divide both sides by 2
    x^3=27
    so x=3
    Dividing both sides by x (for example) let alone x^2 causes you to lose solutions so always factorise when finding solutions for x or whatever variable it may be.
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    (Original post by ManLike007)
    Your solutions are correct to obtain the values 0 and 3.

    However, the answer cannot be 0 and here's why (I think):

    Substituting in x=0

    2(0)-\frac{54}{0^{2}}=0 doesn't work because \frac{54}{0} is undefined which affects the rest of the equation. Divide any number by zero you'll get an error on your calculator
    Thank you
 
 
 
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