If \bo {a}=\stackrel{\^}{\bo {i}}+4 \stackrel{\^}{\bo {j}}, \bo {b}=2 \stackrel{\^}{\bo {i}}-2 \stackrel{\^}{\bo {j}}, \bo {c}=5 \stackrel{\^}{\bo {i}}+9 \stackrel{\^}{\bo {j}}, then \bo {c} is equal to