Помогите решить, надеюсь вы поможите

R1=10    R2=15     R3=4     R4=4     R5=15     R6=10    U=30 B    U1=?   Ro=?==========R12=R1*R2/(R1+R2)=10*15/(10+15)=6R123=R12+R3=6+4=10R1235=R123*R5/(R123+R5)=10*15/(10+15)=6R12345=R1235+R4=6+4=10Ro=R12345*R6/(R12345+R6)=10*10/(10+10)=5 ОмIo=U/Ro=30/5=6 AI6=U/R6=30/6=3 AI1235=I4=Io-I6=6-3=3 AU5=U-I1235*R4=30-3*4=18 BI5=U5/R5=18/15=1.2 AI3=I1235-I5=3-1.2=1.8 AI12=I3U1=U2=I3*R12=1.8*6=10.8 B===========================