Graphing straight lines two-point method
Consider the line y = x + 2.
To graph it, we could draw a table of values, plot the points and join them.
| x | –3 | –2 | –1 | 0 | 1 | 2 | 3 |
|---|---|---|---|---|---|---|---|
| y | –1 | 0 | 1 | 2 | 3 | 4 | 5 |
This line has gradient = 1, y-intercept = 2.
Two points determine a straight line. This line could be draw just with two of the above points.
When x = 1, y = 3.
When x = 3, y = 3 + 2 = 5.
The points (1, 3) and (3, 5) are plotted and the line drawn through them.
The y-intercept is 2 and the gradient = 1.
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