The locus represented by `xy + yz = 0` is

The locus represented by x y + yz=0 is

The angle between the planes represented by 2x ^(2) - 6y ^(2) - 12 z^(2) + 18 yz + 2 zx + xy =0 is

The two planes represented by 12 x ^(2) - 2y ^(2) - 6z^(2) - 7 yz + 6zx - 2 xy =0 are

The angle between the pair of planes represented by equation 2x^(2)-2y^(2)+4z^(2)+6xz+2yz+3xy=0 is

The angle between the pair of planes represented by equation 2x^2-2y^2+4z^2+6zx+2yz+3xy=0 is

The angle between the pair of planes represented by equation 2x^2-2y^2+4z^2+6xz+2yz+3xy=0 is

The angle between the pair of planes represented by equation 2x^(2)-2y^(2)+4z^(2)+6xz+2yz+3xy=0 is

Show that the equations ax+by+r=0 by + cz + p =0, cz+ax+q=0 represents the planes perpendicular to xy, yz, zx - planes respectively.

Find the sum of the following algebraic expressions : 4xy - 3yz + 2zx , 2xy - yz - zx , - xy + 5yz + 6zx