CK12 Content for Algebra

First, kudos to CK12 tech support for the ongoing back and forth trying to troubleshoot my problems, particularly with pdf’s. I still cannot download pdf’s properly on two computers, even after completely wiping and reinstalling browsers. When I have some intermittent success, it is primarily with Opera.

Content-wise, I have mixed feelings about what I am finding available. For example, in the Honors Algebra course, there is some lovely discussion about the real number system, particularly with using proper set notation. Algebraic processes are generally well-explained.

On the other hand, text like this concerns me: “As well, absolute value is always written as |x|. Using this notation can be translated as “the positive value of x”. Um, what about zero? Then, further on, “Keep in mind that the absolute value is the positive value of x.”

I realize that colloquially most people don’t care to differentiate positive from nonnegative, but if we are going to have an accurate textbook, proper terminology is important.

Further in the section on absolute value equations and inequalities is this confusing sentence: “So the linear equation has two solutions when there is an absolute function.” Yes, for that particular equation there were two solutions, but in general there can be zero, one, or two solutions. The use of “function” in this context is also bothersome.

In perusing three different algebra flexbooks, I did not run across multi-step equations with variables on both sides that have infinitely many solutions or no solutions. Perhaps I missed something, but this strikes me as a pretty significant topic. Seriously, most decent pre-algebra textbooks address those situations.

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