For example, if I were saying "This was made by him and I," would it be
possible to write it as "これは彼と私が作りました。"?

Are you allowed to list multiple things as the subject of the sentence?
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2016-08-10T00:21:11.150
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2016-08-10T00:49:33.570
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question
grammar
Are you allowed to use と in front of が?
Yes you can, and your example sentence looks perfectly fine. You don't have to
change the verb form because there is not plural declension in Japanese.
CC BY-SA 3.0
2016-08-10T00:49:33.570
38353
2016-08-10T00:49:33.570
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38351
answer