Hi, just registered here, and I am in need of help with this review problem. I transferred schools and the school that I came from they taught about the Norton Analysis but not when the voltage sources were in parallel. I observed the example problem on this site but the only difference is there is another voltage source below the load resistor, so I only need the equation to find the current through r1 and r2, I can do everything else. So again its like the basic norton problem but with three voltage sources instead of two, one below the load resistor.
Heres the link:

http://www.allaboutcircuits.com/vol_1/chpt_10/9.html

Thank you

 

I'm unclear what you are asking for. You talk about two voltage sources in parallel, yet the circuit you link to doesn't have any voltage sources in parallel. You seem to be asking for formulas that are the result from the analysis of the problem you link to, yet those formulas would only be valid for this circuit.

What you should be striving for is to understand the fundamental principles that underlie the analysis of any circuit. In this case, can you convert B1 and R1 into a Nortan equivalent? Can you convert B2 and R3 into a Nortan equivalent? Having done that, can you combine these two Norton equivalents into one?