Please answer bottom questions as well

2. (12 points) u and v are vectors in 3D space satisyfing 1/ 211 = 5, 11311 -6, 4.5-15. (a) Find 0 the angle between u and v. (b) If u and v lie in the plane r + y - z = 0, find a vector that is either u X v or v X u. u X u or u X v is