Some of the most important functions are linear: they have constant rates of change and are therefore graphed with a straight line. You can draw the line if you know at least two points, but it is better to choose 3, that way you can make sure you have not made a mistake. Do you need to work with linear functions? Start with step 1.
Steps
Method 1 of 2: Method 1: Graph Linear Functions in Standard Form
Step 1. Recognize the standard form of a linear function
Typically, linear functions are written in the form f (x) = ax + b. The "a" represents the gradient of the line, which gives the rate of change of the dependent variable. This is known as the "slope." The "b" represents the intercept with the Y axis. This is the value of the dependent variable or in other words, the value of the function when X = 0.
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For example, let's say you have the function f (x) = x + 5. This is a linear function in its standard form.
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Step 2. Find at least two spots
You will know that your graph will have a straight line because you have a linear function, therefore you really only need two points. In general, however, you should find 3 points instead of 2 to check for accuracy.
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In the example above, you may be able to choose -1, 0, and 1 for the values of X. Solve as shown in the image.
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Step 3. Draw the points
Plot the points in the coordinate system using the values you got from solving the 3 equations.
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In the example above, the chart should look like this.
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Step 4. Connect the dots
For any 2 points, there is only one way to connect them with a straight line. Use a ruler to connect them with a line. You should note that if you graph 3 points and they do not all fall on the same line, you have made a mistake. Go back and calculate everything again.
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In the example above, your chart should look like this.
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Method 2 of 2: Method 2: Graph linear functions in their non-standard form
Step 1. Fix the function to make the Y the subject
If you have a linear function that is not in its standard form, you will need to rewrite it before you can graph it.
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Let's say you have the function 6x - 2y = 4. Move everything but the Y to the left as follows.
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Then divide both sides by -2. Now you have the standard form of a linear function: y = 3x - 2.
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Step 2. Find at least two spots
You will know that your graph will have a straight line because you have a linear function, therefore you really only need two points. In general, however, you should find 3 points instead of 2 to check for accuracy.
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In the rewritten example above, you may be able to choose -1, 0, and 1 as values for X. Solve as follows.
Do Linear Functions Step 6Bullet1
Step 3. Draw the points
Plot the points in the coordinate system using the values you got from solving the 3 equations.
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In the example above, the points should look like this.
Do Linear Functions Step 7Bullet1
Step 4. Connect the dots
For any 2 points, there is only one way to connect them with a straight line. Use a ruler to connect them with a line. You should notice that if you graph 3 points and they do not all fall on the same line, you have made a mistake. Go back and calculate everything again.
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In the example above, the chart should look like this.
Do Linear Functions Step 8Bullet1
Advice
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Functions have an independent variable "X" and a dependent variable "Y". The slope of a line that passes through the points (x1, y1) and (x2, y2) is calculated as follows.
- Linear functions have many practical applications, especially in economics.