Use the node-voltage method to solve for voltage $v$ and current $i$ in Figure E4.2. Assume $I = 20 \text{ mA}$, $R_1 = 5 \text{ k}\Omega$, $R_2 = 10 \text{ k}\Omega$, $R_3 = 10 \text{ k}\Omega$, $R_4 = 20 \text{ k}\Omega$, $R_5 = 20 \text{ k}\Omega$, $R_6 = 7 \text{ k}\Omega$ and $R_7 = 3 \text{ k}\Omega$.
Figure E4.2
Answer:
$v = 50 \text{ V}$, $i = 5 \text{ mA}$