Anonymous
Anonymous asked in Science & MathematicsMathematics · 9 years ago

Solve this system of equations?

d=x+1200

d=2.5x

I'm having issues graphing d=x+1200. I need to know where the point of intersection is.

6 Answers

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  • 9 years ago
    Favorite Answer

    d = x +1200

    The points of intersection are:

    When x = 0, d = 1200, point (0, 1200) = d - int

    When d = 0, x = - 1200, point (- 1200, 0) = x - int

    Join these points with a line, done!

    Solving the system:

    2.5*x = x + 1200

    1.5*x = 1200

    x = 800

    d = 2.5*x

    d = 2.5*800

    d = 2,000

    (800, 2000), answer!

  • 9 years ago

    You do not need to graph them to find point of intersection

    They are simultaneous equations

    'x + 1200' and '2.5x' are both equal to 'd' and are therefore equal to each other so you can write '2.5x = x + 1200' and then begin to solve it

    2.5x = x + 1200 (-x from both sides)

    1.5x = 1200 (divide both sides by 1.5)

    x = 800

    now you know 'x = 800' you can work out 'd'

    use one of the original equations

    d = 2.5x

    d = 2.5*800

    d = 2000

    point of intersection is d = 2000, x = 800

    Source(s): A level maths
  • 9 years ago

    d=x+1200

    d=2.5x

    2.5x=x+1200

    1.5x=1200

    x=800

  • Ed H
    Lv 4
    9 years ago

    Intersects at x=0, d=1200

    Substitute 1st equation into 2nd

    2.5x = x+1200

    1.5x = 1200

    x = 800

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  • 9 years ago

    To fnd the POI, you need to set both equations equal to each other so..

    x+1200=2.5x

    1200=1.5x

    x=800

    Plugging that back in to find y coordinate...

    d=x+1200

    d=800+1200

    d=2000

    Also..

    d=2.5x

    d= 2.5 * 800

    d=2000

    They're both the same so your POI is

    (800, 2000)

    Hope this helps

    Source(s): Math knowledge
  • Anonymous
    9 years ago

    2.5x=x+1200

    1.5x=1200

    x=800

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