解 :x+3y+z = 0 ① 2x+3y-z = 0 ② ① + ② 得 3x +6y =0 即 x +2y =0 y= -0.5x ② - ① 得 x – 2z =0 z = 0.5x (x+2y-7z)/(3x+5y+z) =(x+2y-7z)/(3x+6y-y+z) =(-7z)/(-y+z) =(-7×0.5x)/(0.5x+0.5x) =(-3.5x)/x = ...