Today I was asked the following question:

Is a constant function a subset of linear functions or are the two mutually exclusive?

Here is how I answered:

I think the standards settle this question. They say,

“Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line.”

If it had been desired to exclude the case m = 0, then I think we must believe that it would have said

“Interpret the equation y = mx + b (with m not equal to 0) as defining a linear function…”

Also, the phrase “straight line” is used twice (once in the standard, once in the italicized example). A horizontal line is straight.

*Error in original post has been fixed (originally said b=0 not m=0). Thanks Heather!

• This topic was modified 10 years, 8 months ago by Jason Zimba. Reason: Forgot to tag it the first time
• This topic was modified 10 years, 8 months ago by Jason Zimba.
• This topic was modified 10 years, 8 months ago by Jason Zimba.
• This topic was modified 10 years, 8 months ago by Jason Zimba.