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math (graphing)

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I need to graph "y = -2x+5" and "y = 4/5x-3"...

I don't think it's possible to help graphing on this site.. so can you please tell me any other sites where it would show how to graph those equations?

also, I'm having trouble graphing INEQUALITIES. any help on that??

thanks a lot :)
any help is appreciated.. thanks :)

  • math (graphing) - ,

    here is an easy way to draw a graph of a straight line if you given the equation in the form y=mx+b

    remember that m is the slope and b is the y-intercept and slope = rise/run
    then for y = (4/5)x - 3, rise/run = 4/5
    and the y-intercept is -3

    1. plot the y-intercept (0,-3)
    2. from there count 5 units to the right, then 4 units up, basically doing a run of 5 and a rise of 4.

    join the two points, and you are done.

    for the first one:
    y = -2x + 5 or y = (-2,1)x + 5

    plot (0,5), and from there count 1 unit to the right and then 2 units down, join the points ...

    All done

  • small typo -- math (graphing) - ,

    near the end
    <<y = -2x + 5 or y = (-2,1)x + 5 >>
    should read:

    y = -2x + 5 or y = (-2/1)x + 5

  • math (graphing) - ,

    Thank you VERY much! You're my savior :)

    just one more question.. I NOW understood how to graph equations.. but I still have to graph inequalities, which seems much more complicated from my point of view.

    I've got two inequalities that I have to graph.

    1. y > 2/3x-4
    2. y < -2

    NOTE: Number 1, where it says "y > 2/3x-4"... well under ">" there is a line/dash, as to mean that it's "greater than or equal to". I hope you understand what I mean..

    thanks for your help.. :)

  • math (graphing) - ,

    y ≥ (2/3)x-4

    graph y = (2/3)x - 4, then shade in the region ABOVE that line

    had it been

    y > (2/3)x-4 the boundary is the line
    y = (2/3)x - 4, so draw a dotted line instead of a solid line

    in general if y > mx + b
    draw a dotted line for y = mx + b and shade in the region above the line
    if y < mx + b
    draw a dotted line for y = mx + b and then shade in the region BELOW the line

  • math (graphing) - ,

    what about "y < -2" ????

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