ive been working on about 20 questions of vectors.. but these 5 i cant seem to get.. any help would be much appreciated!

1. Deterine the components of a vector with tail at P (1,1,1), magnitude 3, and in the same direction as a= (-3,-4, 12)

2. The vector v has a magnitude 10 units, positive and equal x and y components, and a z component of 4. Determine v.

3. the vector u= (1,-2,1) Determine 3 different non-collinear vectors that are perpendicular to u. Then show that the 3 vectors determined in the first part of the question are coplanar.

4. Prove that (a-b) x (a+b)= 2(axb)

5. Find the total work done by a 15 N force, F, in the direction of the vector (1,2,2) when it moves particle from O (0,0,0) to P(1,-3,4) and then from P to Q(7,2,5). The distance is measured in metres.