当x-3y+4x=1,2x+y-2z=27,化简x的平方-2xy-3乘以y的平方+2xz+10yz-8乘以z的平方

x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 当x,y,z>0时x+2y+3z=1u=x*x/(x+1)+4y*ysup2/(2y+1)+9z*z/(3z+1)的最小值 z对x的偏导数=(x^2+y^2)/x ,当x=1,z（x,y）=sin y 求z（x,y） 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= 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) {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian x+y+z=2 4x+2y+z=4 2x+3y+z=1 4x+y+z=-3 2x+3y-4z=-10 x+2y-z=-1 3x-y+2z=-1 4x+y+z=5 x-2y-z=-2 x-y-z=1 2x+y-3z=4 3x-2y-z=-1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 阿