化简求值 3x²y-[2xy-2(xy-2/3x²y)]+x²y²,其中x=3,y=-1/_数学解答

化简求值 3x²y-[2xy-2(xy-2/3x²y)]+x²y²,其中x=3,y=-1/3

人气：244 ℃　时间：2019-10-10 06:28:03

解答

xy=-1
3x²y-[2xy-2(xy-2/3x²y)]+x²y²
=-3x-[-2-2(-1-2/-3x)]+1
=-3x+2-2(3x+2)+1
=-9x+2+2+1
=-27-5
=-22