How to Transform a Plane

Suppose you have a plane equation in local space and you’d like to express that plane equation in world space. The plane in local space is written as:
$P := (n, w)$where (n) is the plane normal and (w) is the plane offset.
A point (x) is on the plane if
$n \cdot x = w$Now define a transform (A) as
$A := (R, p)$where (R) is an orthonormal rotation matrix and (p) is a translation vector.