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    Solve:
    3(1-2x) - 5(3x+2) > 0

    I can do everything apart from figure out which way the inequality sign should go (the answers say wou should get -21x>7 and then the final answer is x<-1/3 ).
    Thanks very much
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    (Original post by daviem)
    Solve:
    3(1-2x) - 5(3x+2) > 0

    I can do everything apart from figure out which way the inequality sign should go (the answers say wou should get -21x>7 and then the final answer is x<-1/3 ).
    Thanks very much
    If you are dividing by a negative number, the inequalities switch directions.
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    (Original post by lizard54142)
    If you are dividing by a negative number, the inequalities switch directions.
    That's what I thought but I did:

    -7>21x
    -7/21>x
    -1/3>x

    so got the final answer but not the mark in between
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    (Original post by daviem)
    That's what I thought but I did:

    -7>21x
    -7/21>x
    -1/3>x

    so got the final answer but not the mark in between
    Well it looks like you have rearranged it in a different way than the mark scheme. Perhaps post all your working, from the beginning?
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    (Original post by lizard54142)
    Well it looks like you have rearranged it in a different way than the mark scheme. Perhaps post all your working, from the beginning?
    Sure, I did:

    3-6x-15x-10 > 0

    3-10>6x+15x

    -7>21x

    -7/21>x

    -1/3>x
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    (Original post by daviem)
    Sure, I did:

    3-6x-15x-10 > 0

    3-10>6x+15x

    -7>21x

    -7/21>x

    -1/3>x
    Looks good to me! They probably kept the x's on the left and moved the (3-10) across to the right instead, in the mark scheme.
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    (Original post by lizard54142)
    Looks good to me! They probably kept the x's on the left and moved the (3-10) across to the right instead, in the mark scheme.
    Oh ok, Thanks for your help
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    (Original post by daviem)
    Oh ok, Thanks for your help
    No problem
 
 
 
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