To Be Solved
To Come Undone, To Be Cleared
intransitive verb, ichidan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means solve so the verb vocab version is to be solved. You know that this is the version where something just unties on its own (you're not doing the untying) because you don't have a care (ける) in the world. You just watch things getting untied and don't do it yourself.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: In fact, while you're sitting there with no cares, waiting for things to become untied, you stare down at your toe (と). Really imagine doing that while things around you are getting untied.
もしここにマリアがいたら、こんな数学の問題五秒で解けちゃうよ。マリアにとってはちょちょいのちょいだね。
If Maria were here, this math problem would be solved in five seconds flat. They're a piece of cake for her.
そのナゾナゾ、めっちゃ難しいよ！一時間かかってやっと解けた。
It took me an hour before I finally solved it.
早く誤解が解けるといいんだけど。
I hope the misunderstanding will be cleared up soon.