[tex]R = \frac{U}{I} \ \ \rightarrow \ \ U = R \cdot I \ \ \rightarrow \ \ I = \frac{U}{R}[/tex]
[tex]1. \ \ I = \frac{U}{R} = \frac{6 \ V}{2 \ \Omega} = 3 \ A\\\\2. \ \ R = \frac{U}{I} = \frac{12 \ V}{4 \ A} = 3 \ \Omega\\\\3. \ \ U = R \cdot I = 55 \ \Omega \cdot 4 \ A = 220 \ V\\\\4. \ \ I = \frac{U}{R} = \frac{5 \ kV}{2000 \ \Omega} = \frac{5000 \ V}{2000 \ \Omega} = 2,5 \ A\\\\5. \ \ U = R\cdot I = 3 \ k\Omega \cdot5 \ A = 3000 \ \Omega\cdot 5 \ A = 15 \ 000 \ V = 15 \ kV[/tex]
[tex]6. \ \ R = \frac{U}{I}=\frac{36 \ V}{2 \ A} = 18 \ \Omega[/tex]
