\[ \boxed { \left ( x-3 \right ) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) - \left ( 4\,x-9 \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) + \left ( 3\,x-6 \right ) y \left ( x \right ) =0} \]
Mathematica: cpu = 0.037505 (sec), leaf count = 42 \[ \left \{\left \{y(x)\to \frac {1}{8} c_2 e^{3 x-9} \left (4 x^3-42 x^2+150 x-183\right )+c_1 e^{x-3}\right \}\right \} \]
Maple: cpu = 0.047 (sec), leaf count = 30 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,{{\rm e}^{x}}+{\it \_C2}\,{ {\rm e}^{3\,x}} \left ( 4\,{x}^{3}-42\,{x}^{2}+150\,x-183 \right ) \right \} \]