Straight line graphs. How to plot a sloping line in math using a table of values.
The easiest way to plot a line graph (a sloping line) is to use a table of values, which can also be called a coordinate table. All you need to do is to pick some x coordinates (at least 3, as 2 is not a good idea!), and use your formula to work out the y coordinates. Then plot your points on your coordinate grid, and draw your line through the coordinate points.
Plot the graph of y=2x
The x coordinates that I’m going to pick are 0, 1 and 2. But, you might want to choose different values.
X 0 1 2
Y ? ? ?
To work out the y coordinates in our table of values, you need to substitute these values into your formula y=2x. Do this by multiplying your x coordinates by 2.
X 0 1 2
Y 0 2 4
So our coordinates that our line passes through are (0,0), (1,2) and (2,4).
Plot these onto our coordinate grid, and draw your line through the points. Make sure the line extends all the way across the coordinate grid.
Plot the graph of y = -3x +8
Again, choose 0, 1 and 2 as your x coordinates.
This time we need to times the x coordinates by -3, and add on 8 to find the y coordinates. So our table of values will look like this:
X 0 1 2
Y 8 5 2
So our straight line passes through the points (0,8), (1,5) and (2,2).
Now plot these onto your coordinate grid, and draw your straight line through these points.
Check out these hubs for more help on plotting graphs:
More by this Author
A compound shape is a shape that is made up from other simple shapes. In this article we will be working out the area of a L shape (made up from 2 rectangles). To find the area of a compound shape, follow these simple...
The density, mass and volume triangle is as follows: So if you wanted to work out the density, you would cover up density in the magic triangle to give: Density = Mass/Volume (since mass is above volume) So if...
The surface area of a triangular prism can be found in the same way as any other type of prism. All you need to do is calculate the total area of all of the faces. A triangular prism has 5 faces, 3 being rectangular and...