### 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.