Assertion : The equation `2x^2- 6y^2 + 4z^2 + 18yz + 2zx + xy = 0` represents a pair of perpendicular planes.

Reason : A pair of planes given by `ax^2 + by^2 + cz^2 + 2fyz + 2gzx +2hxy =0` are perpendicular, if `a+b+c= 0`