m+a-a-17m= -16m; 39x-17x+2x-7x=17x; 26y+25m+y+18y=45y+25m; 33y-25b-y+9y=41y-25b; 33d-20x+2d-3x=35d-23x.
m+a-a-17m= -16m; 39x-17x+2x-7x=17x; 26y+25m+y+18y=45y+25m; 33y-25b-y+9y=41y-25b; 33d-20x+2d-3x=35d-23x.