3a�0�5+a�0�5-(2a�0�5-2a）+(3a-a�0�5)=3a�0�5+a�0�5-2a�0�5+2a+3a-a�0�5=(3+1-2-1)a�0�5+(2+3)a=a�0�5+5a
a^2+7a
