Change 5 1/8 to (41)/8 and 9 3/10 to (93/10) get the common denominator which is 40. So multiply top and bottom of (41)/8 by 5 to get (205)/40 and top and bottom of (93)/10 by 4 to get (372)/40.
Then add 205/40 and 372/40 to get 577/40
then turn into a mixed number which is 14 17/40