xy-｛2分之1x²-[3y²-(2x+3y)]-1﹜
=xy-｛2分之1x²-[3y²-2x-3y]-1﹜
=xy-｛2分之1x²-3y²+2x+3y-1﹜
=xy-2分之1x²-3y²-2x-3y+1你确定不会错？。。。确定求当a=-4,b=-3,c=1时，代数式3a²b-[2a²b-(2abc-a²c)-4a²c]-abc的值采纳先