Step 1: Implement Kirchhoff's Current Law (KCL) at nodes \( v_1 \) and \( v_2 \).
Ohm's law and KCL are applied to determine the node voltages.
Step 2: Solve the equation system. The KCL equations, combined with the provided current and resistance data, yield the values for \( v_1 \) and \( v_2 \).
The solution is:
\( v_1 = 10 \, \text{V}, v_2 = 20 \, \text{V} \).
Final Answer: \[\boxed{(1) \, v_1 = 10 \, \text{V}, v_2 = 20 \, \text{V}}\]