1) =6b-12c+5c=6b-7c
2) = -5a+5a-40-14=-54
3) = -6x-10y-6x=-12x-10y
4) =12a+5d-32a+4d=-20a+9d
5) =-7x+2y-14y-6x= -13x-12y
6) =-5a-10b-4a-7b=-9a-17b
7) = 30c+6b-30c+8b=14b
8) = 2a-7+2a+5a-12=9a-19
9) = 36y-18-15y+20=21y+2
10) = -2a+2a-14+14= 0
11) =-6x-12+6x+16+2x=2x+4
12) = -x+y-x+y=-2x+2y
13) = 3x-10+3x=6x-10