Let $\displaystyle V $ be the set of all pairs $\displaystyle (x,y) $ or real numbers and $\displaystyle \Re $ be the feild of real numbers. Define $\displaystyle (x,y) + (x_{1},y_{1}) = (x+x_{1},y+y_{1}), c \cdot (x,y) = (cx,y) $. Prove that $\displaystyle V(\Re) $ isNOTa vector Space.

I can't seem to figure out which of the 10 conditions of Vector Spaces is being violated. My guess is that they involve the ones relating to the external composition since $\displaystyle V $ clearly is an abelian group, but I cannot disprove any of the conditions. Please help!