5x-6y+10x-9y+10x-8y+105x-6y+10y

since addition is commutative, this can be arranged as

5x-6y+10x-9y+10x-8y+105x-6y+10y
5x+10x+10x+105x + -6y-9y-8y-6y+10y
now factor out x and y to get
(5+10+10+105)x + (-6-9-8-6+10)y
I assume you can do the rest all right