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    12^x * 3^3x = 18

    and

    2^(xsquared-x) = 64

    for that one I tried x^2 - x = 6 but I cant get the answer of 3x-2 they are looking for


    thanks
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    for the first one, try expressing the LHS as (something)^x=18, then think of roots...(or you could take natural logs of both sides and simplify for x)

    for the 2nd one, express 64 as powers of 2, i.e, 64 = 2^(something), and equate x^2-x to "something" - then solve the resulting quadratic.
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    (Original post by Hasufel)
    for the first one, try expressing the LHS as (something)^x=18, then think of roots...(or you could take natural logs of both sides and simplify for x)

    for the 2nd one, express 64 as powers of 2, i.e, 64 = 2^(something), and equate x^2-x to "something" - then solve the resulting quadratic.
    thats what I did for the second one but I am not getting the answer they require and I have put the quadratic in wolframalpha and it is not giving the soloution they require either..
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    2^{x^2-x} = 64 = 2^6

    So

    x^2 - x = 6

    Which is the quadratic

    x^2 - x - 6 = 0

    (x-3)(x+2) = 0

    So x = 3 or x=-2

    An answer of 3x-2 doesn't even make sense...
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    (Original post by Noble.)
    2^{x^2-x} = 64 = 2^6

    So

    x^2 - x = 6

    Which is the quadratic

    x^2 - x - 6 = 0

    (x-3)(x+2) = 0

    So x = 3 or x=-2

    An answer of 3x-2 doesn't even make sense...
    It makes perfect sense its just wrong lol
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    (Original post by Noble.)
    2^{x^2-x} = 64 = 2^6

    So

    x^2 - x = 6

    Which is the quadratic

    x^2 - x - 6 = 0

    (x-3)(x+2) = 0

    So x = 3 or x=-2

    An answer of 3x-2 doesn't even make sense...
    I got x=3 or -2 but my book seems to think different...

    So it's the former then?:P

    Are you a math student at oxford?:eek:
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    (Original post by madfish)
    I got x=3 or -2 but my book seems to think different...

    So it's the former then?:P

    Are you a math student at oxford?:eek:
    Yes to both questions.
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    (Original post by Noble.)
    Yes to both questions.
    wow that's pretty awesome that one of the top mathematicians in the UK is helping me with my maths :cool: thanks dude
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    (Original post by Noble.)
    2^{x^2-x} = 64 = 2^6

    So

    x^2 - x = 6

    Which is the quadratic

    x^2 - x - 6 = 0

    (x-3)(x+2) = 0

    So x = 3 or x=-2

    An answer of 3x-2 doesn't even make sense...
    Name:  efeffwq.png
Views: 121
Size:  785 Byteshow can I simplify this? :/
 
 
 
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