5+90m is the solution, to solve:
Distribute 13 to 9 and -6m to remove the parenthesis, and do the same with 14 to 12m and -8, this gives you
117 -78m+168m-112
Then you subtract 78m from 168m, and 112 from 117, which gives you your answer: 5+90m, or 90m+5