"Your shirts are black."

Translation: Deine Hemden sind schwarz.

[diane338886]

Why can't it be "deine" in this case?

[az_p]

Possible German translations for "Your shirts are black":

Deine Hemden sind schwarz - (I'm talking to one person who I'm familiar with)
Eure Hemden sind schwarz - (I'm talking to multiple people who I'm familiar with)
Ihre Hemden sind schwarz - (I'm talking to any number of people who I'm formal with)

Duolingo should accept all three German sentences as a translation from the English, because we don't know the context.

[Paralars1]

It could be. Deine for one person, eure for multiple. The english sentence doesn't clarify this context, so you may report it.

[Raisinnoir]

"Deine" would be correct.

[FitriRahay16]

It is "Adjektiv Deklination" case

[Giorgio810210]

It is plural, shouldn't be ''schwarze''?

[JohanShiju]

I think it is only like that if the color is right before the noun.
Die hunde sind schwarz.
Die schwarze hunde sind schnell.

[fehrerdef]

It is "die schwarzen Hunde". But you are right. adjectives in the predicative position are not declined.