Напряжение U4=36 Найти силу тока I1
R23=R2*R3/(R2+R3)=4*12/(4+12)=3 R234=R23+R4=3+3=6 I23=I4=U4/R4=36/3=12 A U23=I23*R23=12*3=36 B U234=U5=U23+U4=36+36=72 B I5=U5/R5=72/6=12 A I1=I23+I5=12+12=24 A ===========================