This is what I need to find: If a consumer Rp1 is connected between points A and B, derive the computational value of consumer Rp1 at which maximum power is developed. Here is a picture of that circuit. Right circuit is Thevenin equivalent circuit for a left circuit.
Ut = V1/2
How do I find the value of the Rp1 resistor at which maximum power would develop. How do I even get maximum possible power on a resistor?
P.S. V1 can be any value, not only 100V.

 

What theory has to say about this?
https://www.allaboutcircuits.com/textbook/direct-current/chpt-10/maximum-power-transfer-theorem/

 

What theory has to say about this?
https://www.allaboutcircuits.com/textbook/direct-current/chpt-10/maximum-power-transfer-theorem/

That solves my problem. In my university we were learning some basic stuff, but they didn't taught us this and they expect us to know it in order to finish homework. Thank you once again.