I'm digging deep here, Rekt...!!!....LOL!!!!
First....let's convert these to cylindrical coordinates (r, θ, z)
r = p sin Φ = 12 sin 3pi/4 = 6√2
θ = θ = 2pi/3
z = p cos Φ = 12 cos 3pi/ 4 = -6√2
Then....convert these to rectangular (Cartesian) coordinates (x, y, z)
x = r cos θ = 6√2 * cos 2pi/ 3 = 6√2 (-1/2) = -3√2
y = r sin θ = 6√2 * sin 2pi/ 3 = 6√2 * √3/2 = 3√6
z = -6√2
So (x, y , z) = ( -3√2 , 3√6, -6√2 )
So.... x + z = -9√2
