Hi! Could someone please help me with these??

2x - y - 3z = -5

-2x - 6y - z = -3

A vector that is normal to the first plane is < -2, -1, -3 >

A vector that is normal to the second plane is <-2, -6, -1 >

The vectors are not proportional, thus the planes are not parallel

If the dot product of these two vectors = 0, then they are orthogonal

The dot product =

 -2 * -2  + -1 * -6 + -3 * -1   =   4 + 6 + 3  = 13

Thus.......the planes are not orthogonal

Thus, these planes are neither parallel, nor orthogonal

5x - 2y - 4z = 6

-15x + 6y + 12z = -16

The normal vectors are  < 5, -2, -4 >  and <-15, 6, 12>

The vectors ars proportional because 3 times the first equals the second....thus.......these planes are parallel