Excuse my bad english pls. I can't find a proper solution to my problem because i don't know the exact mathematical terms in english.
My problem is how to get the 3 elements of each of 3 vectors named u,v,w with the scalar products:
u°v = -5 u°w = -2 and v°w=9
when i've got the 3 vectors, i have to calculate: ((3u-v)°2w)-((5w-2v)°3u)
I dont really need a full solution unless you feel like giving me one, but a little hint how to solve this would be great.
You don't need to solve for the vectors (in fact, you can't because the system is so underdetermined). Just expand the expression they give you. $(3u-v)\cdot (2w) = 6u\cdot w - 2v\cdot w$. You have both of these values so you can compute this part. Do the same for the other term.