Question

Solve the equation E = V + Ir for r.

Answer 1

The given equation is

`E=V+lr`

First, subtract V from each side.

`\begin{gathered} E-V=V-V+lr \\ E-V=lr \end{gathered}`

Second, divide each side by l.

`\begin{gathered} (E-V)/(l)=(lr)/(l) \\ r=(E-V)/(l) \end{gathered}`

Therefore, the answer is

`r=(E-V)/(l)`