CTM: \(R_1nt\left(R_2//R_3\right)\)
a)\(R_{23}=\dfrac{R_2\cdot R_3}{R_2+R_3}=\dfrac{20\cdot25}{20+25}=\dfrac{100}{9}\Omega\)
\(R_{tđ}=R_1+R_{23}=15+\dfrac{100}{9}=\dfrac{235}{9}\Omega\)
b)\(I_1=I=\dfrac{U}{R_{tđ}}=\dfrac{20}{\dfrac{235}{9}}=\dfrac{36}{47}A\)
\(U_{12}=I_{12}\cdot R_{12}=\dfrac{36}{47}\cdot\dfrac{100}{9}=\dfrac{400}{47}V\)
\(I_2=\dfrac{U_2}{R_2}=\dfrac{\dfrac{400}{47}}{20}=\dfrac{20}{47}A;I_3=\dfrac{U_3}{R_3}=\dfrac{\dfrac{400}{47}}{25}=\dfrac{16}{47}A\)