I do not understand how to rationalize expressions in the denominators. By getting enough factors under the radical in the denominator so that they will all come out of the radical. A problem I'm having trouble with is the 4th root of ((4m^4)(n^2)) times the 4th root of ((7m^2)(n^4)) This is not a "rationalize the denominator" problem because there is no denominator. Did you mean "divided by" instead of "times"? Please repost. Edwin