5x-{2y-3x+[5x-2(y-2x)+3y}
化简
化简就是合并同类项,原式=5x-5x+5x+4x-2y-2y+3y=9x-y
5x-{2y-3x+[5x-2(y-2x)+3y}=5x-2y+3x-[5x-2y+4x]-3y
=8x-5y-5x+2y-4x
=-x-3y