已知｛3x-y+2z=14 4x-8y+z=7 求x+y+z的值

已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=? 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知关于x y z的方程组2x-3y+5z=7 x+2y-3z=8,则4x+y-z= 已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知｛3x-y+2z=14 4x-8y+z=7 求x+y+z的值 已知4x-3y=6z 2x+4y=14z 求2xy/x^+y^ 已知4x-3y=6z 2x+4y=14z 求2xy/x^+y^ 已知|X-8Y|+2(4Y-1)^2+3|8Z-3X|=0求X+Y+Z (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 已知(x+2y)/2=(y+3z)/3=(z+4x)/4,则x:y:z=? 已知x/2=y/3=z/4,则2x+y-z/3x-2y+z=? 已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=? 已知(x+2y)/3=(y+3z)/4=(z+5x)/5,则x:y:z= 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z=? 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z= 已知x-2y+3z=0,x-3y+4z=0,则x:y:z= 已知2x-y-z=0,3x+4y-2z=0,则x：y：z=?