x+(a-b) - (c+d) =x+a-b-c-d;
a+b-c+d
x-1+12-7.5x=11-6.5x
24-20x+17x-10=14-3x
0.6a-0.2+0.3-0.6a=0.1
-13+2.7c-c+8=-5+1.7c
x+(a-b) - (c+d) =x+a-b-c-d;
a+b-c+d
x-1+12-7.5x=11-6.5x
24-20x+17x-10=14-3x
0.6a-0.2+0.3-0.6a=0.1
-13+2.7c-c+8=-5+1.7c