数学啊一道算术

3*x的平房*y-中括号2*X的平方乘*y-（2xyz-x的平方*z)-4*x的平方*z中括号-xyz，x=-2，y=-3，z=1.先合并同类项，再算结果

原式=3x²y-[2x²y-(2xyz-x²z)-4x²z]-xyz=3x²y-2x²y+(2xyz-x²z)+4x²z-xyz=x²y+2xyz-x²z+4x²z-xyz

=x²y+xyz+3x²z=x(xy+yz+3xz)=-2×(6-3-6)=6

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化简求值3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz,其中x=-2,y=-3,z=1, 解:3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz =3x'y-2x'y+2xyz-x'z+4x'z-xyz =x'y-xyz+3x'z =4*(-3)-2*3*1+3*4*1 =-12-6+12 =-6

3x²y-[2x²y-(2xyz-x²z)-4x²z]-xyz=3x²y-[2x²y-2xyz+x²z-4x²z]-xyz

=3x²y-2x²y+2xyz-x²z+4x²z-xyz=x²y+xyz+3x²z

=(-2)²(-3)+(-2)(-3)*1+3(-2)²*1

=-12+6+12

=6.

3x^2*y-[2x^2*y-(2xyz-x^2*z)-4x^2*z]-xyz

=3x^2*y-[2x^2*y-2xyz+x^2*z-4x^2*z]-xyz

=3x^2*y-2x^2*y+2xyz-x^2*z+4x^2*z-xyz

=x^2*y+xyz+3x^2*z

代入x=-2，y=-3，z=1.

原式

=(-2)^2*(-3)+(-2)*(-3)*1+3*(-2)^2*1

=-12+6+12

=6