$${W = (2,0\, \mathrm{N})(-3,0\, \mathrm{m})\hat{\mathrm{i}} \cdot \hat{\mathrm{i}} + (-6,0\, \mathrm{N})(-3,0\, \mathrm{m})\hat{\mathrm{j}} \cdot \hat{\mathrm{i}} \\ = (-6,0\, \mathrm{J})(1) + 0 = \underline{\underline{-6,0\, \mathrm{J}}}}$$