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    which answer is the correct to make y the subject in
    x=3y+2
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    I always get confused with what number I should add or minus or divide or times first
    is it the first number or last number how am I meant to know?
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    Always think about BIDMAS, when rearranging, you work backwards through through the question so the last operation done is the one that you do the inverse of first, so in this case, you would take 2 off both sides of the equation giving x-2=3y then you would divide both sides by 3 to get y on it's own, so (x-2)/3=y, the second one is correct.
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    (Original post by MattSull)
    Always think about BIDMAS, when rearranging, you work backwards through through the question so the last operation done is the one that you do the inverse of first, so in this case, you would take 2 off both sides of the equation giving x-2=3y then you would divide both sides by 3 to get y on it's own, so (x-2)/3=y, the second one is correct.
    why would I start with the +2 instead of the 3y first
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    (Original post by Wildnatxox)
    why would I start with the +2 instead of the 3y first
    The idea is usually to get all the y terms on one side and everything else on the other side then just turn the equation around so the y terms are on the left.

    e.g.

    x = 3y + 2

    x-2 = 3y

    3y = x-2

    Then go from there.
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    (Original post by Wildnatxox)
    why would I start with the +2 instead of the 3y first
    Think of what has happened to x in what order so in this case, x has been multiplied by 3 first then 2 has been added, so you remove the two first working backwards
 
 
 
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