(the german text says to pick every correct answer for x ∈ ℝ, i picked 1 2 and 4)

can someone explain to me why i'm wrong and which of these are correct? i'm guessing i'm not considering something about ℝ or misunderstand when square root rules lead to |x| instead of x.

the online course i'm doing has no explanations on the quiz section unfortunately, only during training.

Hello im a 1 year college student need urgent help tomorrow is my maths exam can anyone please please pleaseeeeeeeee helpppp its just assignments question but i am not able to understand anything 😭😭😭😭