解方程3x+7y+z 4x+10y+z 4x+3y+3z

解方程3x+7y+z 4x+10y+z 4x+3y+3z 解方程：{2x+3y+z=7,x+y+z=4,3x+y-z=-4 解方程{3x -y+z=4 2x+3y-z=12 x+y+z=6 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=4 3Y-X-Z=8 7Z--X-Y=16 这三个方程联立求x y z 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? 已知3X+7Y+Z=6 4X+10Y+z=7 求X+Y+Z=? 3x+7y+z=5 ,4x+10y+z=6 ,x+y+z= 4X+Y+10Z=169 3X+Y+7Z=126 求X,Y,Z 知3x+7y+z=315,4x+10y+z=420,求x+y+z=? 已知3x+7y+z=315和4x+10y+z=420,求x+y+z 解方程组：3x+7y+z=31.5,4x+10y+z=42