1. The problem statement, all variables and given/known data [PLAIN]http://img717.imageshack.us/img717/2285/unledxig.png [Broken] The problem is to verify (v), that is for some x and y in R, we have (-x)(-y) = xy 3. The attempt at a solution (-x)(-y) = (-1)x * (-1)y by Prop 2.7 iv = x*(-1) * (-1)y by M2 = x*(-1*-1) * y by M1 = x*(+1)*y = xy Q.E.D Not sure if I did it right. Now I am going to throw in another question. My prof did a lot of proofs in class in the similiar manner as me (except for being wrong...). The thing is that they all look so silly. Like why do I have to go throw all this trouble just to show that (-1)(-1) = +1? That took like 4 lines. This is like math made unnecessarily hard.