解方程组；1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=

解方程组；1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z= 解方程组2x+y-z=7 x+y+z =1 2x-y-z=5 解方程组：x-2y+z=-1,x+y+z=2,x+2y+3z=-1 已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1 解方程组2x+y-3z=1,x-2y+z=6,3x-y+2z=9求x,y,z的值 解三元一次方程组 x+y+z=26 x-y+xz=1 2x-y+z=18 (x+y-z)(x-y+z)= 1.x+y+z=26 x-y=0 2x+z=y+18解方程组,要过程! 2.x-y=0 x-z=-1 x+y+2z=2 三元一次方程组数学题x+2y+2z=33x+y-2z=72x+3y-2z=10x-y=2z-x=3y+z=-1x-y-z 解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 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、z满足方程组：x+y-z=6；y+z-x=2；z+x-y=0 求x、y、z的值