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Equations of Lines  Lesson 132
We next recalled how to graph horizontal and vertical lines:
Which is summarized as follows:
We also learned today how to determine the equation of a line in y = mx + b format. This is a two step process:
 Determine the slope (m). This is often accomplished by finding the slope of a line that we know to be parallel or perpendicular to the line we're trying to define. It can also be done by using the slope formula if we know the coordinates of two points on the line.
 Determine the yintercept. This is accomplished by plugging the coordinates of a point we know is on the line into the equation y = mx + b (remember that we already know m) and solving for b.
So, for example...we might do the following:
