一
0.8[x+(3x-6)] = [x+(3x-6)] -13.20.2[x+(3x-6)] =13.2x+(3x-6) = 664x-6=664x=72x=18
(x+(3x-6))*0.8-(x+(3x-6))=-13.20.2(x+(3x-6)=13.2x=18