In the sentence "Herr Minister, sind Sie mit den Ergebnissen [...] zufrieden?", "den Ergebnissen" is plural and dative. This is NOT accusative! The reason is the dative preposition "mit". The dative plural article is "den" and the plural noun gets an extra "n". The normal plural of "Ergebnis" is "Ergebnisse", but in dative plural it turns into "Ergebnissen".
Here's another example to make this clear: The sentence "I'm playing with the dogs" (der Hund; plural: die Hunde) is: "Ich spiele mit den Hunden.". "den Hunden" is dative plural of "der Hund".
And it doesn't matter whether it's a "der", "das", or "die" word, e.g. "der Hund", "das Ergebnis", "die Blume" => "mit den Hunden", "mit den Ergebnissen", "mit den Blumen". The only exception are words that take an "s" to form the plural. They don't take an extra "n" in dative plural, e.g. "das Auto - die Autos" => "mit den Autos".