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    Okay, this may be an easy question for most A-Level students but i’m only 13 ok

    9^(3x-6) = (1/3)^y

    Find an equation for y

    Use your answer to solve these simultaneous equations:
    9^(3x-6) = (1/3)^y
    and
    y = 2x + 4

    Pls help idgi
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    (Original post by frankielogue)
    Okay, this may be an easy question for most A-Level students but i’m only 13 ok

    9^(3x-6) = (1/3)^y

    Find an equation for y

    Use your answer to solve these simultaneous equations:
    9^(3x-6) = (1/3)^y
    and
    y = 2x + 4

    Pls help idgi
    Try to make both sides have the same base

    e.g.if you had this:

    \displaystyle 8^x = 4^{2x+1}

    \Rightarrow \left(2^3\right)^x = \left(2^2\right)^{2x+1}

    \Rightarrow 2^{3x} = 2^{4x+2}

    \Rightarrow 3x = 4x+2


    Yours is harder than this example but see if you can use a similar method. Post your working/thoughts if you get stuck.
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    (Original post by notnek)
    Try to make both sides have the same base

    e.g.if you had this:

    \displaystyle 8^x = 4^{2x+1}

    \Rightarrow \left(2^3\right)^x = \left(2^2\right)^{2x+1}

    \Rightarrow 2^{3x} = 2^{4x+2}

    \Rightarrow 3x = 4x+2


    Yours is harder than this example but see if you can use a similar method. Post your working/thoughts if you get stuck.
    Not sure if this is 100% correct but I got

    \displaystyle (3^2)^{3x-6} = (3^-1)^y

    \Rightarrow \left 3^{6x-12} = -y

    Is this correct?
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    (Original post by frankielogue)
    Not sure if this is 100% correct but I got

    \displaystyle (3^2)^{3x-6} = (3^-1)^y

    \Rightarrow \left 3^{6x-12} = -y

    Is this correct?
    I don't know if you've finished editing your latex but you've made a mistake in changing (3^{-1})^y into -y. The 3 has disappeared.

    You should use 'preview post' before posting to check your latex looks okay.
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    (Original post by notnek)
    I don't know if you've finished editing your latex but you've made a mistake in changing (3^{-1})^y into -y. The 3 has disappeared.

    You should use 'preview post' before posting to check your latex looks okay.
    isn’t -1 * y = -y?
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    (Original post by frankielogue)
    isn’t -1 * y = -y?
    It is but your 3 has disappeared. Correct version:

    \left(3^{-1}\right)^y = 3^{ \left( -1 \times y\right) } = 3^{-y}
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    (Original post by notnek)
    It is but your 3 has disappeared. Correct version:

    \left(3^{-1}\right)^y = 3^{ \left( -1 \times y\right) } = 3^{-y}
    Ohhh I see😂 Do you then solve :
    \displaystyle 6x-12 = -y
    to get the answer for y? this was my main problem - not sure what to do next
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    (Original post by frankielogue)
    Ohhh I see😂 Do you then solve :
    \displaystyle 6x-12 = -y
    to get the answer for y? this was my main problem - not sure what to do next
    The question wants you to find an equation for y in terms of x. You just need to divide both sides by -1 and then you're done.

    If you had already reached this point when you asked this question then you should have posted all your working at the start.
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    (Original post by notnek)
    The question wants you to find an equation for y in terms of x. You just need to divide both sides by -1 and then you're done.

    If you had already reached this point when you asked this question then you should have posted all your working at the start.
    My bad. I see that but I don’t get the simultaneous equations part.
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    (Original post by frankielogue)
    My bad. I see that but I don’t get the simultaneous equations part.
    You've changed 9^(3x-6) = (1/3)^y into a simple linear equation. So now you have two linear equations which you can solve in the normal way.
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    (Original post by frankielogue)
    Okay, this may be an easy question for most A-Level students but i’m only 13 ok

    9^(3x-6) = (1/3)^y

    Find an equation for y

    Use your answer to solve these simultaneous equations:
    9^(3x-6) = (1/3)^y
    and
    y = 2x + 4

    Pls help idgi
    A-level Mathematics actually scares me. So glad i won't have to take it.
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    (Original post by notnek)
    You've changed 9^(3x-6) = (1/3)^y into a simple linear equation. So now you have two linear equations which you can solve in the normal way.
    No you have to solve these equations:
    9^(3x-6) = (1/3)^y
    2x + 4


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    NEVER MIND I UNDERSAND TYSM


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