Jamie's age is n. (given)
Brian's age is 2n. (given)
Half of Brian and Jamie's present age is (n +2n)/2 = 3n/2.
Let m represent Morgan's age now. Then
... m + 8 = 2 + 3n/2 . . . . . in 8 years, Morgan's age will be 2 more than ...
Subtract 8 to find Morgan's present age:
... m = 3n/2 - 6 . . . . Morgan's present age