\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) =-{\frac { \left ( {x}^{2}a \left ( 1-a \right ) -b \left ( x+b \right ) \right ) y \left ( x \right ) }{{x}^{4}}}=0} \]
Mathematica: cpu = 0.665585 (sec), leaf count = 61 \[ \left \{\left \{y(x)\to \text {DifferentialRoot}\left (\{\unicode {f818},\unicode {f817}\}\unicode {f4a1}\left \{\unicode {f818}''(\unicode {f817}) \unicode {f817}^4+\left (-a^2 \unicode {f817}^2+a \unicode {f817}^2-b \unicode {f817}-b^2\right ) \unicode {f818}(\unicode {f817})=0,\unicode {f818}(1)=c_1,\unicode {f818}'(1)=c_2\right \}\right )(x)\right \}\right \} \]
Maple: cpu = 0.094 (sec), leaf count = 62 \[ \left \{ y \left ( x \right ) ={\it \_C1}\, \left ( \left ( 2\,ax+b \right ) {{\sl I}_{a}\left ({\frac {b}{x}}\right )}+{{\sl I}_{a+1}\left ( {\frac {b}{x}}\right )}b \right ) +{\it \_C2}\, \left ( \left ( 2\,ax+b \right ) {{\sl K}_{a}\left ({\frac {b}{x}}\right )}-{{\sl K}_{a+1}\left ( {\frac {b}{x}}\right )}b \right ) \right \} \]