Question

IR + Ir = E solve for I

Answer 1

   
$\displaystyle \\ IR + Ir = E \\ I(R + r) = E \\ \\ \boxed{I = \frac{E}{R+r}}$

Answer 2

IR+Ir=E
I(R+r)=E
I=E/(R+r)

Answer: I=E/(R+r)