Question

If you know the power rating of an appliance and the current the appliance uses, you can calculate the voltage of the line it is attached to by

Answer 1

if their are choices you should list them. The givens are pretty specific though.

W = E * I is the answer
E (voltage) = W/I is a more refined answer. <<< answer.

Answer 2

dividing the power by the current. is the answer