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

Other question

If A is a matric satisfying

-8(A^3)-10(A^2)+8A+I=0

show that A is invertible with

(A^-1)=-1(-8(A^2)-10A+8I)

Im assuming thatIis the identity matrix but other than that im lost.