=((x^2+3x)-(2mx+6m))/((x^2+3x)+(2mx+6m))=(x(x+3)-2m(x+3))/(x(x+3)+2m(x+3))=(x+3)(x-2m)/((x+3)(x+2m))=(x-2m)/(x+2m)
=((x^2+3x)-(2mx+6m))/((x^2+3x)+(2mx+6m))=(x(x+3)-2m(x+3))/(x(x+3)+2m(x+3))=(x+3)(x-2m)/((x+3)(x+2m))=(x-2m)/(x+2m)