a^2+2ab+b^2-2ac-abc+c^2 =(a+b)^2-2c(a+b)+c^2+2bc-abc =(a+b-c)^2+bc(2-a) =(m/2+1+m/2+2-m/2-3)^2+(m/2+2)(m/2+3)(2-m/2-1) =m^2/4+(m^2/4+5m/2+6)(1-m/2) =（m^2）/4+（m^2）/4+5m/2+6-（m^3）/8-）（5m^2）/4-3...