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Help with 12 (definitely not 11) in my pic Watch

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    Anyone? thanks
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    anyone?:/
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    How can you get rid of the root 2 on the rhs?
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    (Original post by Matureb)
    How can you get rid of the root 2 on the rhs?
    times the bottom and top of the fraction by root 2

    what do I do after that?:/
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    (Original post by madfish)
    times the bottom and top of the fraction by root 2

    what do I do after that?:/
    Do that, then bring all x's to one side and factorise, then divide by the bracket for your solution. For simplification sake remember then x\sqrt 8=2x\sqrt 2 as another method and then divide by the coefficient given to your whole x term
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    Or multiply everything by root 2. Then rearrange.
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    (Original post by Robbie242)
    Do that, then bring all x's to one side and factorise, then divide by the bracket for your solution. For simplification sake remember then x\sqrt 8=2x\sqrt 2
    how do we get it in the form they are looking?

    edit, i got it

    #thanks again robbiee
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    (Original post by madfish)
    how do we get it in the form they are looking?
    11+\frac{3x}{\sqrt 2}=2x\sqrt 2 -> 11+\frac{3x\sqrt 2}{2}=2x\sqrt 2 therefore notice that 2x\sqrt 2 - \frac{3}{2}x\sqrt 2=\frac{\sqrt 2}{2} From here divide and rationalise
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    (Original post by Robbie242)
    11+\frac{3x}{\sqrt 2}=2x\sqrt 2 -> 11+\frac{3x\sqrt 2}{2}=2x\sqrt 2 therefore notice that 2x\sqrt 2 - \frac{3}{2}x\sqrt 2=\frac{\sqrt 2}{2} From here divide and rationalise
    yea i got it, thanks very much robbie
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    (Original post by madfish)
    yea i got it, thanks very much robbie
    No problem
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    (Original post by Robbie242)
    No problem
    How do we do 12 a?:/
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    (Original post by madfish)
    How do we do 12 a?:/
    Note that (x^a)^b=x^{ab} From this you can use your power to simplify them to ^3 and ^-3 Furthermore, set f(x)=5 then subtract 5 as it is on the end just leaving your x term accordingly, now you have a standard equation Solve it. (you may have to use inverse powers tell me when you get here)
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    (Original post by Robbie242)
    Note that (x^a)^b=x^{ab} From this you can use your power to simplify them to ^3 and ^-3 Furthermore, set f(x)=5 then subtract 5 as it is on the end just leaving your x term accordingly, now you have a standard equation Solve it. (you may have to use inverse powers tell me when you get here)
    i am up to (2x)^3=(3x)^-3

    btw you are class at maths robbie... are your teachers not gutted you proved them wrong?:P
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    (Original post by madfish)
    i am up to (2x)^3=(3x)^-3

    btw you are class at maths robbie... are your teachers not gutted you proved them wrong?:P
    Ok now this is how I'd do it this may seem a bit weird but its what I do
    2x^3=\frac{3}{x^3} from this we notice that x^3 works well here, from this we can assert that 2x^6=3 therefore x^6=\frac{3}{2} I am going to put my method here as well to see if it works though, by substituion let x^3=k 2k=3/k-> 2k^2=3 k^2=3/2 so k=\sqrt \frac{3}{2}} Don't forget plus or minus, similarly this means its true.

    so solve x^6=\frac{3}{2} and I think you get the right answer. They aren't they're quite happy to see were topping league tables; selfish *******s
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    (Original post by Robbie242)
    Ok now this is how I'd do it this may seem a bit weird but its what I do
    2x^3=\frac{3}{x^3} from this we notice that x^3 works well here, from this we can assert that 2x^6=3 therefore x^6=\frac{3}{2} I am going to put my method here as well to see if it works though, by substituion let x^3=k 2k=3/k-> 2k^2=3 k^2=3/2 so k=\sqrt \frac{3}{2}} Don't forget plus or minus, similarly this means its true.

    so solve x^6=\frac{3}{2} and I think you get the right answer. They aren't they're quite happy to see were topping league tables; selfish *******s
    so we just take the 6th root of 3/2 ? how on earth we do that without a calculator?
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    (Original post by madfish)
    so we just take the 6th root of 3/2 ? how on earth we do that without a calculator?
    Seems a bit farfetched tbh, you could write it as x=\sqrt[6]{\frac{3}{2}}
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    (Original post by Robbie242)
    Seems a bit farfetched tbh, you could write it as x=\sqrt[6]{\frac{3}{2}}
    I know.. what a rotten question..

    haha
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    (Original post by madfish)
    I know.. what a rotten question..

    haha
    Am I right btw? I'm not sure haha
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    (Original post by Robbie242)
    Am I right btw? I'm not sure haha
    I don't think so but you are very close... the answer is 1.14 to 3dp according to my book
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    (Original post by Robbie242)
    I don't think so but you are very close... the answer is 1.14 to 3dp according to my book
    You should be taking the 6th root of 9/4, not 3/2~

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