2m+3分之2-3-2m分之3+4m的平方-9分之2m+15=2/(2m+3)-3/(3-2m)+(2m+15)/(4m^2-9)=(4m-6)/(2m+3)(2m-3)+(6m+9)/(2m+3)(2m-3)+(2m+15)/(4m^2-9)=(4m-6+6m+9+2m+15)/(4m^2-9)=(12m+18)/(4m^2-9)=6(2m+3)/(2m+3)(2m-3)=6/...