$\lim_{x \rightarrow 3} \left(\frac{ \frac{ \mathrm{d} }{ \mathrm{d}x} \left( {x}^{2}-6x+9 \right) }{ \frac{ \mathrm{d} }{ \mathrm{d}x} \left( {x}^{2}-9 \right) }\right)$
Find the derivative$\lim_{x \rightarrow 3} \left(\frac{ 2x-6 }{ \frac{ \mathrm{d} }{ \mathrm{d}x} \left( {x}^{2}-9 \right) }\right)$
Find the derivative$\lim_{x \rightarrow 3} \left(\frac{ 2x-6 }{ 2x }\right)$
Factor out $2$ from the expression$\lim_{x \rightarrow 3} \left(\frac{ 2\left( x-3 \right) }{ 2x }\right)$
Cancel out the common factor $2$$\lim_{x \rightarrow 3} \left(\frac{ x-3 }{ x }\right)$
Evaluate the limit$\frac{ 3-3 }{ 3 }$
Simplify the expression$0$