"Saya tidak suka sofa yang putih."

Translation: I do not like the white sofa.

[Serfive]

What about 'I do not like white couches'?

[Jake929031]

I think "I do not like sofas that are white" is better.

I don't think Duolingo is doing a good job of translating "yang". It should be used like "that is" or "which is" when used like that.