3x-y+2z=3 (1)2x+y-3z= -11 (2)x+2y+z=2 (3)(1)+(2)得5x-z= -8 (4)(2)*2-(3)得3x-7z= -24 (5)(4)*7-(5)得32x= -32 所以x= -1把x=代入(4)得 z=3 把x= -1,z=3代入(1)得y=0所以 x= -1;y=0;z=3.