Complex numbers are used in electronics to describe the current in an electric circuit. Ohm’s law relates the current in a circuit, I, in amperes, the voltage of the circuit, E, in volts, and the resistance of the circuit, R, in ohms, by the formula E = IR. Use this formula to solve Exercises 55–56.

Find E, the voltage of a circuit, if I = (4 - 5i) amperes and R = (3 + 7i) ohms.