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    hi,

    im trying to find the x and y values for the following equation: y = x(x^2 - 4)

    when x = 0 y= -4
    but not sure what to do when y = 0
    thanks
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    i think that you have to either make the part in the braket =0. Or the actual x value being timesd by the bracket.

    e.g. 0(0^2 -4)

    or 2(2^2 - 4)





    answer = 2 or 0
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    (Original post by Hrov)
    i think that you have to either make the part in the braket =0. Or the actual x value being timesd by the bracket.

    e.g. 0(0^2 -4)

    or 2(2^2 - 4)





    answer = 2 or 0
    how did you come to do this? 2(2^2 - 4) why did you choose to sub x=2 ?
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    when y=0 you want the equation to be equal to 0
    so if the part in the bracket is equal to 0, ie 2^2 -4 what ever this is timesd by outside of the bracket (2) the equation will still equal 0.

    i.e. look in your brackets and make = to 0.
    make your x value equal to what is being take off of it. so in this case what squared minus 4 = 0. answer being 2
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    or -2
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    (Original post by Hrov)
    when y=0 you want the equation to be equal to 0
    so if the part in the bracket is equal to 0, ie 2^2 -4 what ever this is timesd by outside of the bracket (2) the equation will still equal 0.

    i.e. look in your brackets and make = to 0.
    make your x value equal to what is being take off of it. so in this case what squared minus 4 = 0. answer being 2
    i get it now
    thnks
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    like mf2004 says, dont forget the -2
 
 
 

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