3x的平方乘y-[2x的平方乘y-(2xy的平方-x的平方乘z)-4x的平方乘z]-xyz,当x=2,y=3,z=1时,求值
问题描述：
3x的平方乘y-[2x的平方乘y-(2xy的平方-x的平方乘z)-4x的平方乘z]-xyz,当x=2,y=3,z=1时,求值
答
3x²y-[2x²y-（2xy²-x²z）-4x²z]-xyz
=3x²y-[2x²y-2xy²+x²z-4x²z]-xyz
=3x²y-2x²y+2xy²+3x²z-xyz
=x²y+2xy²+3x²z-xyz
=x²（y+3z)+xy（2y-z）
=4（3+3)+6(6-1)
=54
答
原式=3x²y-(2x²y-2xy²+x²z-4x²z)-xyz
=3x²y-(2x²y-2xy²-3x²z)-xyz
=3x²y-2x²y+2xy²+3x²z-xyz
=x²y+2xy²+3x²z-xyz
=4*3+2*2*9+3*4*1-2*3*1
=12+36+12-6
=54
答
3x的平方乘y-[2x的平方乘y-(2xy的平方-x的平方乘z)-4x的平方乘z]-xyz,当x=2,y=3,z=1时,求值=3x²y-2x²y+2xy²-x²z+4x²z-xyz=x²y+2xy²+3x²z-xyz=2²×3+2×2×3²+3×...