Straight line graphs
All straight lines take the form of y = mx + c. Where m is the gradient (steepness) and c is the y-intercept (cuts the Y axis).
Table of Values
•Use a table for values of ‘x’ to generate coordinates with ‘y’.
•A straight line through these points creates the graph of the equation.
•Use a table for values of ‘x’ to generate coordinates with ‘y’.
•A straight line through these points creates the graph of the equation.
Example 1: Draw the graph of y = 2x - 5
Let's use value of x from 1 to 5.
Let's use value of x from 1 to 5.
When x = 1
y = 2 x 1 - 5 y = 2 - 5 = -3 |
When x = 2
y = 2 x 2 - 5 y = 4 - 5 = -1 |
When x = 3
y = 2 x 3 - 5 y = 6 - 5 = 1 |
When x = 4
y = 2 x 4 - 5 y = 8 - 5 = 3 |
When x = 5
y = 2 x 5 - 5 y = 10 - 5 = 5 |
If you're still not sure, have a look at this video where I explain the process of how we create the table, work out the y-intercept and plot the graph.
Working out the y-intercept
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Plotting the graph
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