Hello, Potato!

The vector is normal to the plane

and the vector is normal to a second plane .

Do the two planes necessarily intersect if they are both extended indefinetly?

If the two planes do intersect, find a vector which is parallel to their line of intersection.

Two planes are parallel if their normal vectors are parallel (equal).

. . Since , the planesintersect.will

Their line of intersection has the vector: .

. . Do you see why?

. . Therefore: .