first observer that log(x−3) means that the value of x must be >3 because a log can't be negative or 0. Now in order for the product of both log terms to be =1 both must evaluate to 1 or 1 term must be the inverse of the other. This is only possible if x=10 because log(10)=1 and the terms are additive inside the log and greater than 1. No matter what number x takes on it will be headed in both directions by 3 and they will never be equal.