Помогите упростить: ((a^3-9a)/(a^2+6a+9))-a

[latex] \frac{ a^{3} -9a}{ a^{2}+6a +9} -a=[/latex] [latex]= \frac{a( a^{2}-9 )}{(a+3) ^{2} } -a=[/latex] [latex]= \frac{a(a+3)(a-3)}{(a+3) ^{2} } -a=[/latex] [latex]= \frac{a(a-3)}{a+3} -a= \frac{a(a-3)-a(a+3)}{a+3} = \frac{ a^{2}-3a- a^{2}-3a }{a+3} = -\frac{6a}{a+3} [/latex]