The rule is: If two exponentials with the same base are equal, and the base is positive and not equal to 1, then the exponents are equal. Since the base of both exponentials is e = 2.718ยทยทยท, which is positive and not equal to 1, we can set the exponents equal to each other, and ignore the common base. x = 4x+27 I think you can solve that pretty easily. Edwin