Calculus 8th Edition

$\lt 1,0,-1\gt$
Given: Line of intersections of the planes $x+y+z=1$ and $x+z=0$ $n_1=\lt 1,1,1\gt$ and $n_2=\lt 1,0,1\gt$ Take the cross product of the two normal vectors. $n_1 \times n_2=\lt 1,1,1\gt \times \lt 1,0,1\gt$ $=\lt 1,0,-1\gt$