3x平方y-[2x平方y-(2xyz-x平方z)-4x平方z]-xyz x=-2 y=-3 z=1 怎么化简求值
问题描述:
3x平方y-[2x平方y-(2xyz-x平方z)-4x平方z]-xyz x=-2 y=-3 z=1 怎么化简求值
答
3x²y-(2x²y-(2xyz-x²z)-4x²z)-xyz
=3x²y-2x²y+2xyz-x²z+4x²z-xyz
=x²y+3x²z+xyz;
=4*(-3)+3*4*1+(-2)(-3)1
=-12+12+6
=6