\(\left(R_1ntR_2\right)//R_3\)
\(R_{12}=R_1+R_2=10+10=20\Omega\)
\(R_{tđ}=\dfrac{R_{12}\cdot R_3}{R_{12}+R_3}=\dfrac{20\cdot20}{20+20}=10\Omega\)
\(U_{AB}=U_3=U_{12}=24V\)
\(\Rightarrow I_1=I_2=\dfrac{U_{12}}{R_{12}}=\dfrac{24}{20}=1,2A\)
\(I_3=\dfrac{U_3}{R_3}=\dfrac{24}{20}=1,2A\)