解方程:a=38.857-60x-15y-63z 2800x+70y+70z=1540 70x+4.86y+z=80.1
(x+y-z)(x-y+z)=
消去法解方程组{X+Y=70{Y+Z=140{X+Z=90求X、Y、Z
X+Y+Z=?
f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)
解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18
解方程:{2x+3y+z=7,x+y+z=4,3x+y-z=-4
解方程 .{x+y-z=11 {y+z-x=5 {z+x-y=1
解方程{3x -y+z=4 2x+3y-z=12 x+y+z=6
3x-y+z=3 2x+y-3z=11 x+y+z=12 解方程
x*(y-Z)=27,y*(x-Z)=35,Z*(x+y)=28三个方程正整数解
x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y----
已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz