1. The problem statement, all variables and given/known data F and G and H are vectors in D-3 a and b are real numbers Proof that F+G=G+F Proof that (F+G)+H=F+(G+H) 2. Relevant equations 3. The attempt at a solution I did put F=a,b,c and G=a1,b1,c1 and H=a2,b2,c2 and put that in. I just don´t know if that´s enough. anyone who knows?