Breakdown of Hast du deinen Ausweis und das Formular?
du
you (informal singular)
und
and
haben
to have
dein
your (informal)
Questions & Answers about Hast du deinen Ausweis und das Formular?
Why is it deinen Ausweis instead of just dein Ausweis?
The verb hast (from haben, to have) requires the accusative case for its direct object—the thing that you have. Since Ausweis is a masculine noun (der Ausweis), the word for "your" must take the masculine accusative ending -en, making it deinen.
Is das Formular also in the accusative case here?
Yes, it is! Both Ausweis and Formular are direct objects of the verb hast, so they are both in the accusative case. However, Formular is a neuter noun. For neuter (and feminine) nouns, the accusative case looks exactly the same as the nominative case, so the article remains das.
If I wanted to say "your ID and your form," would I use deinen for the form too?
No, you would use dein. Because Formular is neuter, its accusative form for "your" is dein Formular. You cannot carry over the deinen from Ausweis because the two nouns have different genders and need their own matching endings.