"The new soup is not tasty."
Translation:Nowa zupa nie jest smaczna.
Well... "niesmaczna" isn't exactly "not tasty". After all, "not tasty" covers also "neutral in taste", while "niesmaczna" is rather "untasty", if only this was a word. The closest English words seems to be "unpalatable"... but that actually feels too strong.
So ok, I guess I can add it here... but please refrain from trying to suggest it and similar words everywhere ;)
Because you can only use the construction "X to Y" if both X and Y are noun phrases. In a way, "to" in such a construction is like "=". You could say for example "The new soup = tasty food", but not "The new soup = tasty".
More info here: https://www.duolingo.com/comment/16373167