Hi guys, this is part c of a series of problems, where I'm now stuck.

Let P be the plane 2x + y - z = 1

Point Q is at (0, 0, -1)

Take n = 2i + j - k as a normal vector of the plane P.

Decompose the vector QO into the sum of two vectors; one of them is parallel to n and the other one is orthogonal to n.

Any help greatly appreciated!