1. The problem statement, all variables and given/known data In the following circuit I need to find current I1 if the given parameters are E1=0V,E2=15V,E3=60V In the second case, given parameters are I2=100mA,I3=40mA,E1=30V,E2=E3=0V In both cases, R2=R3=R4=R5=300 ohm 2. Relevant equations Using reciprocity theorem for DC circuits. 3. The attempt at a solution I used reciprocity theorem on the second case, moving the source E1 between the nodes where I3 flows. From there I1=-I3=-40mA. Is this correct? This is the second case. Could someone help how to find current I1 in the first case? Thanks for replies.