how can you tell if two planes are parallel SolutionIf two p

how can you tell if two planes are parallel ?

If two planes are parallel, their normals will be parallel (which means the vectors are scalar multiples)

Plane with equation ax + by + cz = d has normal vector (a, b, c). Compare the two normal vectors. If they are parallel (i.e. one is a multiple of the other) the planes are parallel.