2x-3y-z+1 = 0 , x+y+z = 0 , 两式相加 得 3x-2y+1 = 0,取 y = -1, 得 x = -1, z = 2, 即交线上点 M(-1, -1, 2)所求平面法向量是| i j k||1 1 1||2 -3 -1|= 2i +3j -5k所求平面方程是 2(x+1)+3(y+1)-5(z-2) = 02x+3y-5z+15 = 0