由里向外去括号：原式=-（-x-y)-[-x+(4x-x+y+z-3x)+2z]=x+y-(-x+y+z+2z)=x+y+x-y-3z=2x-3z由外向里去括号：原式=-(-x-y)+x-[4x-(x-y-z)-3x]-2z=x+y+x-4x+(x-y-z)+3x-2z=2x+y-4x+x-y-z+3x-2z=2x-3z你的问题没写完,不...