R2//(R1nt[R5//(R3ntR4))
\(=>R1345=R1+\dfrac{R5\left(R3+R4\right)}{R5+R3+R4}=7\Omega=>Rtd=\dfrac{R2.R1345}{R2+R1345}=14\Omega\)
\(=>I3=I4=I34=>U5=U34=I34.R34=0,5.\left(R3+R4\right)=3V=>I5=\dfrac{U5}{R5}=1A=>I1=I5+I34=1,5A=>U1345=U2=1,5.R1345=10,5V=U2=Um=>I2=\dfrac{U2}{R2}=1,5A\)