We have the next formula
[tex]R=\frac{V}{I}[/tex]And we must solve it for I and for V.
1. Solving the formula for I
[tex]\begin{gathered} R\cdot I=\frac{V}{I}\cdot I \\ \frac{1}{R}\cdot R\cdot I=V\cdot\frac{1}{R} \\ \text{ So, the formula for I is:} \\ I=\frac{V}{R} \end{gathered}[/tex]2. Solving the formula for V
[tex]\begin{gathered} R=\frac{V}{I} \\ R\cdot I=\frac{V}{I}\cdot I \\ \text{ So, the formula for V is} \\ V=R\cdot I \end{gathered}[/tex]