#8: 14.95+7.55=22.50 so the cost of the DVD is $22.50 and the subtraction equation is, 22.50-7.55=14.95
#10: 2/3+1/3=1 so m=1
#12: 7/9+1/3=10/9 or 1 1/9
The simplified form is 4m^5
Trey designed 105 games, so he designed 70 more games. The way the question is worded is weird.