# When and where were textbooks that use set notation for basic algebra solutions?

A past question described a school where many teachers insisted that answers to algebra problems had to be phrased in set-theoretic language or notation. For example, when asked to solve $$2x+3=6−x$$, students were expected to say that the solution set was $$\{1\}$$, not that $$x=1$$. In a comment, the OP wrote:

I think that there is a history in my department of using a particular textbook that stresses this distinction, and that over the past several decades, it has crept into the culture here to the point where it is codified in course descriptions.

Now I'm wondering who the authors of such textbooks were. It feels like old math education, in the vein of New Math... Presumably the makers were American? Unless a school was importing their textbooks from overseas?

• I've seen a number of College Algebra texts that talk about but do not focus on set-builder notation for solutions in their chapters on inequalities (openstax.org/books/algebra-and-trigonometry/pages/…, for example). To clarify, is your question about the phenomenon in the linked question, of the answer to a "solve" problem explicitly needing to be presented as a solution set? Jun 1 at 5:55
• @TomKern - Yes. "Solve" problems with their answers presented in set notation. Jun 1 at 13:13
• Have you reached out to the OP from the linked question? He may have a list. Jun 1 at 14:19
• @NickC - How do I do that on here? Jun 1 at 14:36
• @NickC - Comments don't bump questions up in the sorting? I thought it did, but I guess this stack is low traffic enough that I can't tell the effects of bumps vs edits... Jun 1 at 17:47