How To

How to Graph Linear Equations

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By eHow Contributing Writer
(82 Ratings)

Line them up!

Difficulty: Moderately Easy
Instructions

Things You'll Need:

  1. Step 1

    Draw a pair of perpendicular lines. These are your axes (the plural of "axis"). Label the horizontal axis "x" and the vertical axis "y." Label several different values, both positive and negative, of x and y on both axes. This is the scale of the graph.

  2. Step 2

    Remember that your equation should be in the form y = mx + b (if it is in a different form, solve for y in terms of x).

  3. Step 3

    Draw a dot on the y axis at y = b. This is the y-intercept of the graph (the point at which the graph crosses the y-axis).

  4. Step 4

    Choose a value for x other than 0 and mark this on the x-axis you've drawn. Lightly draw a vertical line that crosses this value of x on your x-axis.

  5. Step 5

    Plug the x value you chose into your equation.

  6. Step 6

    Solve for y. Lightly draw a horizontal line that crosses this value of y on your y-axis.

  7. Step 7

    Make a dot where the two lines you just drew intersect.

  8. Step 8

    Draw a straight line between this dot and the y-intercept. Extend this line in both directions to the edges of your graph. This line is the graph of your equation.

Tips & Warnings
  • The value "m" in y = mx + b is the slope of the graph. The slope is the ratio of vertical change to horizontal change between two points on the graph.
  • Example: The graph of the equation y = 2x + 5 has a slope of 2 and crosses the y-axis at y = 5.

Comments  

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tacojohn48 said

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on 8/23/2008 In an equation of the form y=mx+b b will always be where the line crosses your y axis. Think of it as the point where x=0 and plug that into your equation so y=(6*0)+7 or y=7

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on 4/13/2008 To find the y intercept you mention y = b is this a general 'rule of thumb' or will this change i.e if y = 6x + 7 then would y = 7?

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on 4/13/2008 To find the y intercept you mention y = b is this a general 'rule of thumb' or will this change i.e if y = 6x + 7 then would y = 7?

Anonymous

Anonymous said

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on 6/30/2006 To test to see if the equation is true, after graphing put in (0,0) for y. If it's less than or greater than the number then you draw lines toward the the side of the 0. Example y=2x+3. Put in (0,0) for y. Since it's true, you draw lines toward the 0.

Anonymous

Anonymous said

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on 11/22/2005 If the line is straight, you have a linear line. If it is not, because it is curved or crooked, then you can tell that it is not.

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