Consider the set of all solutions to the system of equations x + 2y + 3z + u = 4 5x − 3y + 2z − 6u = 0 as a subset of r 4 . do the following: (a) explain how you can or could determine that this solution set defines a plane in r 4 . include in this explanation what the solution set may look like if it is not a plane in r 4 . (b) parameterize the plane defined by the system of equations above, using the parameter variables s and t. (c) describe the space that this system determines if these equations were describing a subset of r 5 , with coordinates (x, y, z, u, v). how can we adapt the parameterization from part (b) to parameterize this new space in r 5 .