Sentence construction: "This and this yield/s"

I am writing the following sentence and would like to know which option is proper English (or if both are proper):

Option 1: Squaring both sides of (9) and dividing by 2 yields: [math equation]

Option 2: Squaring both sides of (9) and dividing by 2 yield: [math equation]

So the issue is "yield" versus "yields." Option 1 sounds better to me as a native English speaker. The sentence was actually written by my non-native co-author in the option 2 form. This made me wonder which is correct. Option 2 might be validated because both things together can be viewed as plural. Option 1 might be validated because the procedure of both things together is singular. Or perhaps both options are fine?

[Note that the "(9)" in the sentence refers to a numbered equation given earlier in the paper.]

Solution 1:

It's only the two actions taken together as a single unit that yields anything, so the singular is correct. It's not like both of those operations taken each on its own will produce that same result.