Translation:They seemed to be happy with their lives.
'Conjugation' is only for verbs. "Happy" is an adjective. It's merely singular or plural. (Or in some cases masculine/feminine)
But yes, it should be "felices".
Why doesn't "feliz" agree with "ellas" in this sentence? Is it an error or a language thing I don't understand?
I notice that no one from Duolingo has responded to Madziu's similar comment from two months back.
Errors in a teaching medium should be corrected ASAP to prevent propagation of the error.
I would think so, I wrote "They seemed like they were happy with their lives." It marked it as incorrect but it seems right to me.
why doesn't appear work here? they used to appear to be happy with their lives?
I put the same but now I can see I was wrong as 'parecían' is the imperfect past conjugation. appear is present and would be parecen.
Duo uses the Spanish word 'aparecer' (to appear,to show up,to turn up) as the translation for 'appear' while 'paracer' (to seem, to look, to appear to be) is translated to seem (in this cased seemed and parecian) In English it would be fine to say "They appeared to be happy with their lives" but "They seemed to be..." is a better translation.