先化简,再求值:(8x-3y)-(4x+3y-2)+2z其中x=0.5,y=-1,z=2
化简求值:(2x-y+3z)(-2x-y-3z)-(x+2y-3z)2,其中x=1,y=-1,z=1.
先化简再求值:3x-2y-[2x+2y-(2xyz+x+2z)-4x+2z]-xyz,其中x=-1,y=-2,z=3.
3道高数题,1,函数F(x,y,z)=(e^x) * y * (z^2) ,其中z=z(x,y)是由x+y+z+xyz=
已知x::y:z=3:4:5,(1)求x+y分之z的值;(2)若x+y+z=6,求x,y,z.
已知x/2=y/3=z/4,求下列各式 (1)(x+y+z)/x (2)(x-y+2x/(x-y-2z)
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
先化简在求值3x^y-[2x^2y-(2xyz-x^2z)-4x^2z]-xyz,其中x=-2,y=-3,x=1
(1)3x+4z=7;2x+3y+z=9;5x-9y+7z=8 (2)3x+4y+z=14;x+5y+2z=17;2x+
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/(除以)x-y+z的值.
已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z都不为0,求(3x*x+y*y+4z*z)/(5x*x+y*
已知3x=4Y,5Y=6Z,求 (1)x:y:z;(2)x+y/y+z.