Let X be a random variable. If m is a positive integer, the expectation E[( X - br], if it exists, is called the mth moment of the distribution about the point b. Let the first, second, and third moments of the distribution about the point 7 be 3, 11, and 15, respectively. Determine the mean µ of X; and then find the first, second, and third moments of the distribution about the point µ.