Can resistors be used to use a 110 volts rated hairdryer in a 220 volt source?

Resistors could be used if you can find resistors with a high enough wattage rating to dissipate the heat that they will generate. Your best bet is to purchase a voltage adapter. The adapter is just a transformer that steps down the voltage from 220 to 110 volts. Locate on the hair dryer what the wattage draw is and then match the transformer (adaptor) to that wattage output.