Which of the following equations is correct ?

Which of the following equation is correct ?

Which of the following equation is correct ?

If '+' means '-:','xx' means '+', '-' means 'xx' and '-:' means '-' then which of the following equation is correct ?

Which of the following equation is correct in the context of kohlarusch 's law

Which of the following equation is correct in the context of kohlarusch 's law

See the electrical circuit shown in this figure. Which of the following equations is a correct equation for it ?

See the electrical circuit shown in this figure. Which of the following equations is a correct equation for it ?