Answer
See explanation.
Work Step by Step
Transmitting power at extremely high voltages means that the same power can be supplied using much lower current, equation 25.17.
The heat loss in the wiring can be expressed as $P=I^2R$. For a given wire size, using lower currents makes the process much more efficient.
The main disadvantage is that high voltages are more dangerous than low voltages, and a system of transformers must be used to step down the voltage from the 750 kV down to the 120-240V that is typically used in homes and businesses.
