u={2,3}
v={-1,2}
z=u-v

Show[
Graphics[{Red,Arrow[{{0,0},u}]},Axes->True,AxesLabel->{x,y},LabelStyle->Directive[Large],Background->White],
Graphics[{Blue,Arrow[{{0,0},v}]}],
Graphics[{Dashed,Blue,Arrow[{{0,0},-v}]}],
Graphics[{Dashed,Blue,Arrow[{u,u-v}]}],
Graphics[{Black,Arrow[{{0,0},z}]}]
]