kai ki
Lv 5
kai ki 發問於 科學及數學數學 · 1 十年前

F3 to F4 Maths coordinate geometry of straight lines

Prove that the straight line passing though A(2,3) and B(-4,-6) passes through the origin.

I do not understand what answer do the question want?

Please answer my question...

Please explain!!!

圖片參考:http://tw.yimg.com/i/tw/ugc/rte/smiley_1.gif

thanks....

圖片參考:http://tw.yimg.com/i/tw/ugc/rte/smiley_1.gif

2 個解答

評分
  • 1 十年前
    最愛解答

    Prove that the straight line passing though A(2,3) and B(-4,-6) passes through the origin.

    I do not understand what answer do the question want?

    first, we need to find the slope

    slope = 3+6/2+4 = 9/6 = 3/2

    then , we find the equation of this straight line

    by the formula y-y(1) = m[x-x(1)]

    equation = y-3 = 3/2(x-2)

    y-3 = 3/2(x-2)

    2y - 6 = 3x - 6

    2y-3x=0

    the eqaution of the straight line : 2y-3x=0

    put x = 0 into the equation 2y-(3)(0) = 0 , y= 0

    when x=0, y=0, so line is pass through the origin

    2008-08-22 20:53:57 補充:

    Prove that the straight line passing though A(2,3) and B(-4,-6) passes through the origin.

    其實我同上面都用左附加數方法

    正確中三用的方法

    應該用斜率計

    同一正線上, 任何兩點的斜率都會一樣

    即係我地計左成條斜率係3/2

    再計A點同O點的斜率, 又係3/2

    再計B點同O點的斜率, 都係3/2

    即係A,O,B,3點係同一條線

  • Ellen
    Lv 6
    1 十年前

    equation of the straight line passing though A(2,3) and B(-4,-6) is:

    (y-3)/(x-2)=(-6-3)/(-4-2)

    (y-3)/(x-2)=-9/-6

    2(y-3)=3(x-2)

    2y-6=3x-6

    3x-2y=0

    put O(0,0) into 3x-2y=0

    3(0)-2(0)=0

    it satisfies the equation that means the line 3x-2y=0 passes through the origin.

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