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    Here is my working so far:

    (2x-1)(x+4)<0

    2x-1<0
    2x<1
    x<1/2


    x+4<0
    x<-4


    How do I then know which sign to flip for the answer? I don't understand. Thanks.
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    -4 < x < 1/2

    What other way would you put it?
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    (Original post by Smug Life)
    -4 < x < 1/2

    What other way would you put it?
    Why is it that though and not: x<-4 and x>1/2
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    (Original post by will_jg)
    Why is it that though and not: x<-4 and x>1/2
    Have you tried to draw a parabola for that? It doesn't make sense. How could something be greater than 1/2 and less than -4 at the same time?
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    Here's what we were taught. Please excuse the handwriting!

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    (Original post by will_jg)
    Here is my working so far:

    (2x-1)(x+4)<0

    2x-1<0
    2x<1
    x<1/2


    x+4<0
    x<-4


    How do I then know which sign to flip for the answer? I don't understand. Thanks.
    I always suggest sketching the curve so you can 'see' it.
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    (Original post by will_jg)
    Here is my working so far:

    (2x-1)(x+4)<0

    2x-1<0
    2x<1
    x<1/2


    x+4<0
    x<-4


    How do I then know which sign to flip for the answer? I don't understand. Thanks.
    surely just plugging x=5 should tell you?
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    (Original post by will_jg)
    Here is my working so far:

    (2x-1)(x+4)<0

    2x-1<0
    2x<1
    x<1/2


    x+4<0
    x<-4


    How do I then know which sign to flip for the answer? I don't understand. Thanks.
    You can't just work with each bracket in isolation! If one bracket is negative then the other one has to be positive, and vice versa. So you'll get 2 conditions to combine for each possibility.
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    Sketch the curve ALWAYS. Never ever don't do it.

    From the inequality you see (2x-1)(x+4)<0

    <0 meaning below the axis so you want the solutions below the axis. That's why you get what they said above.
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    I get it now thanks everybody!
 
 
 
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