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Math Help - algebra problem

  1. #1
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    Unhappy algebra problem

    Haai!! =D

    I have lots of homework due for tomorrow unfortunatlyy

    And i've done half of what we're supposed to do, which is some of it, it's

    2(5+2x) = 17
    and my teahcer taught me to times the 2 to the 5 and the 2
    which gives me
    4x+10=17
    then to do the same both sides by taking 10
    so 4x = 7
    then to divide both sides by 4 to give me the answer x=1.75 (hopefully, did that bit on a calculator)

    Annnnnnnnyways....now i got like loads more to do, but they are different, and i don't understand how to work them out...the first and easiest one is

    2x - 1 = x + 3

    I really don't understand it...i really don't understand maths.

    Can anyone help? Atall?

    Thankss if you can and willl....i will love you =D

    xx


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  2. #2
    Member
    Joined
    Aug 2007
    Posts
    144
    Hi Tanyar-ox,

    We have 2x-1=x+3 . Now add a 1 to both sides; 2x-1+1=x+3+1 which gives 2x=x+4 . Now minus an x from both sides; 2x-x=x-x+4 which yields x=4 .

    Hope this helps.
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  3. #3
    is up to his old tricks again! Jhevon's Avatar
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    New York, USA
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    Quote Originally Posted by Tanyar-ox View Post
    Haai!! =D

    I have lots of homework due for tomorrow unfortunatlyy

    And i've done half of what we're supposed to do, which is some of it, it's

    2(5+2x) = 17
    and my teahcer taught me to times the 2 to the 5 and the 2
    which gives me
    4x+10=17
    then to do the same both sides by taking 10
    so 4x = 7
    then to divide both sides by 4 to give me the answer x=1.75 (hopefully, did that bit on a calculator)

    Annnnnnnnyways....now i got like loads more to do, but they are different, and i don't understand how to work them out...the first and easiest one is

    2x - 1 = x + 3

    I really don't understand it...i really don't understand maths.

    Can anyone help? Atall?

    Thankss if you can and willl....i will love you =D

    xx


    the idea is to move things from one side to the other by performing their opposite operations on both sides. so if you want to move a +1 from one side to the next, then you must -1, etc. your objective is to get the x one one side by itself, and everything else on the other side. this is what Sean did

    by the way, not feeling the neon-green font. we're not all as young as you, please be considerate of our (perhaps poor) eyesight
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  4. #4
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    Cornwall
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    Unhappy

    Sorrrry about the colourrr.

    Any chance theres any easier ways of explaining this? I still reallly don't get it...sorrry

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  5. #5
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Tanyar-ox View Post
    Sorrrry about the colourrr.

    Any chance theres any easier ways of explaining this? I still reallly don't get it...sorrry

    lets go through the steps a bit slower, showing you what i mean

    we have 2x - 1 = x + 3

    we know that our objective is to get x = something, right? so to do that, we want to get all the x's to one side and everything else to the other side. so first, choose what side you want to get x on. i choose the left, since i have more x's over there to begin with. why move a lot of people when i can move a little, right?

    so ok, i want to get all x's on the left. but there is an x on the right, how do i get rid of it? i see that i have a +x on the right, that is, it is adding. i need to perform the opposite operation on both sides, that means i have to subtract x from both sides. so do that, we get

    2x - 1 - x = x + 3 - x

    now, remember, we can add in any order, so i can do the 2x - x on the left, this leaves me with 1x, right, but we don't write the 1, that is awkward, so just write x. on the right, we have x - x, which gives me zero x's left. so we have successfully gotten rid of the x on the right. thus we have

    x - 1 = 3 ...................., with me so far? hold on, we're not done

    i see that there is a -1 on the left. i only want x's on the left, this is unacceptable. so i have to get rid of -1. again, i do this by performing its opposite operation on both sides. since the 1 is being subtracted, i must add 1 to both sides. thus we get

    x - 1 + 1 = 3 + 1

    the -1 + 1 = 0, so i am only left with x on the left, and the 3 + 1 = 4 on the right, thus we end up with

    x = 4


    got it?
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