加减法解:2x+3y=-1,3x+4y-3z=-7,-2x+3y+3z=1
用加减法解{2X+3Y+Z=38 3X+4Y+2Z=56 4X+5Y+Z=66
用加减法解三元一次方程组 2x+3y+z=38 3x+4y+2z=56 4x+5y+z=66
{5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-
x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=?
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
解方程一;{x+y-z=6,x-3y+2z=1,3x+2y-z=-7.②{3x+4z=7,2x+3y+z=9,5x-9y
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
x+2y=3 x+y+z=36 2x+y+z=15 2y=3z x-y=1 x+2y+z x-z=-1 2x+z-y=1
若x-2y+4z=1,x+3y-7z=0,则y:z=?
已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z.
x+2y-z=1 3x-3y+z=2 3x+3y+z=7
解方程:{2x+3y+z=7,x+y+z=4,3x+y-z=-4