Here are the questions:

I kinda lost my notes with the theory explaining this stuff since its from a previous semester.. So i'd be very thankful to anyone who can help me with these questions, thanks.

 

For the first exercise, use Kirchoff's voltage Law in the circuit mesh, and take into account that the current \(i_{\tiny{N}}\) flows through R too. You will come up with a second grade equation that has the current as an unknown. Choose the value that makes sense.

As for the second problem, I 'm not sure what the exercise wants you to do. What is hidden beyond the cropped border?