What's the difference between this and the Hungarian for "What are cheap houses like?" I omitted the definite article from my English translation and my submission was marked wrong due to the missing article.
It should be fine by now.
Why is ‘the’ necessary here? Can’t this be a general question?
Yes, it can be.
"What are the cheap houses like?" (the cheap houses mentioned) = "Milyenek az olcsó házak?"
"What are cheap houses like?" (in general) = "Milyenek az olcsó házak?"
So yeah, we express both in the same way.