Effingham, IL

6/27/2010

My first math donation in chalk occurred outside of the Helen Matthes Library. Something about Effingham was compelling, and how could I pass up the “Matthes”? So, the project began with a little riff on slope-intercept form.

Many people recall slope-intercept form. Maybe not the name, but folks tend to feel a slight jog in their brain upon mention of *y* = *mx* + *b*. There are two points labeled, though hard to see, in the graph: (0, *b*) and (1, *b* + *m*). (I learned quickly the pale peach color wouldn’t do so well for text.)

The first point is of course the *y*-intercept arriving on the scene when 0 takes the place of *x* in the form. Multiple *m* by 0, add *b*, and voila *y* = *b* when *x* = 0.

The second point… It’s easy, and I won’t spoil it. You tell me, if you’d like.

y=m+b when x=1

Nice. If you were in my Algebra I class, I would ask you to show your work, and I think you know what you are doing.