Suppose that vector (p, q and r) are three non-coplanar vectors in R3. Let the components of a vector s, along vector (p, q and r) be 4, 3 and 5, respectively. If the components of a vector s along vector(– p + q + r), vector (p – q + r) and vector (– p – q + r) are x, y and z, respectively, find the value of 2x + y + z.