"We are not satisfied with these presidents."
Translation:S těmito prezidenty nejsme spokojení.
No, there are several endings of plural instrumental depending on the declension paradigm. For example:
- masc. hard paradigms -y: animate: pány, předsedy; inanimate: hrady
- masc. soft paradigms -i: animate: muži, soudci; inanimate: stroji
- feminine paradigms - always -mi: ženami, růžemi, písněmi, kostmi
- neuter paradigms - various endings: městy, moři, kuřaty, staveními
The neuter instrumental plural endings are actually "-y", "-i", "-mi", and "-(a)ty" (but the "kuře" paradigm has this "-t-" extension in all cases). :D
The plural instrumental is so messy that common Czech actually uses a single ending for ALL nouns: "-Xma" where X is "a", "e", or nothing. So, it's sort of a single ending with a few variations :D It makes things clearer though, because for example with "muži", you don't know if it's plural nominative or plural instrumental, while in common Czech the plural instrumental is "mužema". It's a bit ironic though that this "-ma" used to be the instrumental dual ending, which is now obsolete.
Yes, dual is a special form when there's 2 of something. It used be a thing in all Slavic languages, but only Slovenian has it today. It doesn't exist in Czech anymore, only as a remnant for a few select nouns - like "dvěma rukama" (with two hands) vs. "se třemi ženami" (with three women) - but it's not limited to amounts of 2 anymore, it's used instead of plural with some nouns (hands, feet, ears, eyes), you'll learn about it in a later skill. The modern "-ma" ending in common Czech that I mentioned works for all instrumental plural, I only said it used to be a dual ending.