Typo...? in page 157: Chapter 3.3, Exercise 38

[MetallicCrimson]

Since English isn't my first language either (and I'm not well versed in math lingo), I have the following question:
Is
k is equal to and opposite n
correct? Wouldn't it be better as "opposite of"? Same as
either k is not equal to n or k is not opposite n.

[spamegg1]

I think you might be right, "x is the opposite of y" is correct.
Many examples here under "opposite: noun"
https://www.merriam-webster.com/sentences/opposite

"x is opposite y" is also correct but only when "opposite" is used as an adjective to mean directions or placement. Like "The jewelry store is opposite the cafeteria".
There are some examples of that here https://www.wordhippo.com/what-is/sentences-with-the-word/opposite.html

If "opposite" is used as a noun and means contrast, or completely different, then it should be "the opposite of".

[spamegg1]

Closed by #50 thanks!