x/(x+1)-[(x+3)/(x+1)]*(2x^2+6x)/(x^2+6x+9)
=x/(x+1)-[(x+3)/(x+1)]*[2x(x+3)]/(x+3)^2
=x/(x+1)-[(x+3)/(x+1)]*[2x/(x+3)]
=x/(x+1)-2x/(x+1)
=-x/(x+1)
=-2/(-2+1)
=2