I am stuck on the following problems, both from university intro algebra course
Find the parametric equations of the line which intersects each of followinglines orthogonally: x=-9+3t , y=-5+t , z=-3+t and x=-3+2t , y=-7+3t , z=-17+t
If A is a matric satisfying
show that A is invertible with
Im assuming that I is the identity matrix but other than that im lost.