text: Radek: Bro i have another question T_T i know you wanna kick my ass...
  Radek: Can i ask?
  Artur: Haha
  Artur: No worries
  Artur: Sure, ask, I will answer as soon as I get some time
  Artur: If I know the naswer :D
  Radek: Bro in the previous homework you used this equasion, let me take a picture, it will be faster
  Radek: <file_picture>
  Radek: did you mean this
  Radek: <file_picture>
  Artur: Yeah
  Artur: Did I really use the first one? Really :D?
target: Artur used the wrong equation in his previous homework, which Radek noticed.