Graphing Lines Using y = mx + b Slope Intercept

The most common way students learn to graph lines is using y=mx + b or the slope intercept method.  This is a great method because it’s straight forward and easy.  However a linear equation must be in y=mx + b form to use the slope intercept method of graphing.  Let’s look at a quick example.  The line 3x -7 = 2y is not in y = mx + b format so we could not use the slope intercept method to graph this line unless we rewrite it into y=mx + b which we can do without too much trouble.  Now let’s take a look at the line y=4x + 1 this line is in slope intercept y=mx + b form so we can easily graph it- how fun!  So how exactly do we graph a line in slope intercept form?  Well all we need to do is follow a few steps.  Ok step 1 is to plot the y-intercept( this is the point the line crosses the y-axis) and this number is the “b” pat of y=mx + b.  In our example y=4x + 1 the y-intercept would be 1.  Now onto our next step and for this we will use the “m” part of y=mx + b.  The “m” part is the slope of the line.  What we do is use the slope(rise/run) to plot a second point.  Specifically we count the rise and run from y-intercept to plot a second point (watch the lesson video to see how this is done).  Lastly we connect the two points we plotted and presto we have a line!  Graphing lines using the slope intercept method is a skill you must master so I really encourage you to relax and watch the lesson video below- good luck!


Concepts to remember about graphing lines using the slope intercept method:

1. the slope intercept method can be used when linear equations are written in y=mx + b form
2. the first step is to plot the “b” or y-intercept
3. next use the “m” or slope to find a second point
4. draw a line through the two points
5. if a line is not in y=mx + b form you simply can rewrite it such that it is and graph using the slope intercept