Urgently ask the master to solve the problem of electrician principle! Solve problems, ideas and formulas in detail!

These topics are the basic theory of circuits. In short, I suggest you take a good look at the theory of the circuit, the regulation of the direction of potential and current, Kirchhoff's law and so on. If you understand them, you can tell them one by one. And you may not understand why, so you should read by yourself.

"Please tell the experts about the detailed steps, formulas and ideas of solving these problems! And the meaning in the picture! (Be sure to be detailed! I want to eat ready-made, turn around and let me think about the next step. I won't, I want to be comprehensive! ) This is very important! I will increase the reward points if I answer well! "

See what you mean, it's no use telling you! ! !

Not if I don't tell you, and not after I tell you! ! !