Slope-Intercept Form for Linear Equations: y = mx + b

The slope-intercept form, y = mx + b, for writing linear equations is very popular because it tells you a lot about the line.  The "m" value in the equation is the "slope" of the line and the "b" value in the equation is the "y-intercept," or the point where the line will cross the y-axis on a graph. 

Here's a good website that explains how to use the slope-intercept form of an equation to graph the line:  http://www.gradeamathhelp.com/graphing-linear-equations.html

I like how the website helps you to remember to start with the y-intercept because you can think of "b" as "beginning."  Then you use the slope to move from your starting point  by thinking of "m" as "move."  

Here's a little clip from the website...

Here's another website that helps you explore how the slope and y-intercept values will change the appearance of the line:  http://www.math-play.com/Slope-Intercept/Slope_Intercept.html

To check your understanding of Linear Equations in the y = mx + b form, try to answer these questions:

1)  What is slope?  How does the "m" number in the equation tell you how to move?

2)  What types of numbers for "m" will give you steep slopes?  What types of numbers will give you flat slopes?  What value for slope will give you a completely flat, or horizontal line?

3)  What does a linear equation with a positive slope look like?  What does a linear equation with a negative slope look like?

4)  How does the "b" value change the appearance of the line?  What can you say about a line that has a "b" value of 0?