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Math Help - Find the coordinates of these points..

  1. #1
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    Find the coordinates of these points..

    two different points on the line y=2 are each exactly 13 units from the point (7,14). Draw the picture of this situation, and then find the coordinates of these points.

    ^so i tried setting up a cartesian coordinate plane and set the points out but i didnt know what else to do. experts?
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  2. #2
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    Quote Originally Posted by gabriel View Post
    two different points on the line y=2 are each exactly 13 units from the point (7,14). Draw the picture of this situation, and then find the coordinates of these points.

    ^so i tried setting up a cartesian coordinate plane and set the points out but i didnt know what else to do. experts?
    Solve \sqrt{(x-7)^2+(12)^2}=13 for x.
    You should find two values.
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  3. #3
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    i got stuck on sqrt -13x + 158 = 13
    ^ and would x be an (i) integer?
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  4. #4
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    Quote Originally Posted by gabriel View Post
    i got stuck on sqrt -13x + 158 = 13
    The part is red is comply wrong.
    You need to learn to do basic algebraic operations.
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  5. #5
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    ^how is this wrong?

    ok so the problem is sqrt of (x-7)^2 + 12^2=13
    so to solve this is did the following:
    foiled (x-7)^2 = x^2+14x+14
    while doing that, the problem would be sqrt of x^2-14x+14 (+) 144 = 13
    and so on what is wrong with that?
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  6. #6
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    Quote Originally Posted by gabriel View Post
    ok so the problem is sqrt of (x-7)^2 + 12^2=13
    so to solve this is did the following:
    foiled (x-7)^2 = x^2+14x+14
    while doing that, the problem would be sqrt of x^2-14x+14 (+) 144 = 13
    and so on what is wrong with that?
    FOIL, in my view, is a useless idea.
    (x-7)^2=(x-7)(x-7)=x^2-7x-7x+49=x^2-14x+49

    If you cannot do these simple operations, then you are going to have a most difficult time doing pre-calculus.
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  7. #7
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    Quote Originally Posted by gabriel View Post
    ^how is this wrong?

    ok so the problem is

    \sqrt{(x-7)^2 + 12^2}=13

    so to solve this is did the following:

    foiled (x-7)^2 = x^2+14x+14 .....this is incorrect, you should be multiplying the -7's..not adding 7+7

    while doing that, the problem would be sqrt of x^2-14x+14 (+) 144 = 13
    and so on what is wrong with that?

    (x-7)^2=(x-7)(x-7)=x(x-7)-7(x-7)=x(x)+x(-7)-7(x)-7(-7)

    =x^2-7x-7x+49=x^2-14x+49

    x^2-14x+49=(13)^2

    Also x^2-14x is not equal to -13x

    x-14x=-13x
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  8. #8
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    so what do i do when i get
    sqrt of x^2-14x+49 = 13^2 or (169)
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  9. #9
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    You do not understand this problem at all do you?
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