x+y+z=2 4x+2y+z=6 x-y+z=-2

题目

x+y+z=2 4x+2y+z=6 x-y+z=-2
还有一个：x+y+z=26 x-y=1 2x-y+z=18

答案

x+y+z=2 ①4x+2y+z=6②x-y+z=-2③①+③得2x+2z=0x+z=0把x+z=0代入①y=2把y=2代入①和②4x+4+z=6∴{4x+4+z=6④ x+2+z=2⑤④-⑤得3x+2=4x=2/3把x=2/3代入⑤z=-2/3∴原方程组的解为{x=2/3 y=2 z=-2/3x+y+z=26① x-y=1②...