(3.) In the figure below, $R_1 = 8.00 \, \Omega$, $R_2 = 2.00 \, \Omega$, $R_3 = 5.00 \, \Omega$ and the batteries have
emfs $\mathcal{E}_1 = 6.0 \, V$, $\mathcal{E}_2 = 12.0 \, V$, and $\mathcal{E}_3 = 4.0 \, V$.
(a.) What is the current flowing through $R_1$ ?
(b.) What is the current flowing through $R_3$ ?