\(R=R1+\left(\dfrac{R2.R3}{R2+R3}\right)=18+\left(\dfrac{30.20}{30+20}\right)=30\Omega\)
\(I=U:R=60:30=2A\)
\(I=I1=I23=2A\left(R1ntR23\right)\)
\(U1=R1.I1=18.2=36V\)
\(\Rightarrow U23=U2=U3=U-U1=60-36=24V\)(R2//R3)
\(\left\{{}\begin{matrix}I2=U2:R2=24:30=0,8A\\I3=U3:R3=24:20=1,2A\end{matrix}\right.\)
\(R_1nt\left(R_2//R_3\right)\)
a) \(R_{tđ}=R_1+\dfrac{R_2\cdot R_3}{R_2+R_3}=18+\dfrac{30\cdot20}{30+20}=30\Omega\)
b) \(I_1=I_{23}=I_m=\dfrac{U}{R_{tđ}}=\dfrac{60}{30}=2A\)
\(U_2=U_3=U_{23}=I_{23}\cdot R_{23}=2\cdot\dfrac{30\cdot20}{30+20}=24V\)
\(I_2=\dfrac{U_2}{R_2}=\dfrac{24}{30}=0,8A\)
\(I_3=\dfrac{U_3}{R_3}=\dfrac{24}{20}=1,2A\)
