\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) =- \left( {\frac { \left( 1-{\it al1}-{\it bl1} \right) {\it b1}}{{\it b1}\,x-{\it a1}}}+{\frac { \left( 1-{\it al2}-{\it bl2} \right) {\it b2}}{{\it b2}\,x-{\it a2}}}+{\frac { \left( 1-{\it al3}-{\it bl3} \right) {\it b3}}{{\it b3}\,x-{\it a3}}} \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) -{\frac {y \left( x \right) }{ \left( {\it b1}\,x-{\it a1} \right)  \left( {\it b2}\,x-{\it a2} \right)  \left( {\it b3}\,x-{\it a3} \right) } \left( {\frac {{\it al1}\,{\it bl1}\, \left( {\it a1}\,{\it b2}-{\it a2}\,{\it b1} \right)  \left( -{\it a1}\,{\it b3}+{\it a3}\,{\it b1} \right) }{{\it b1}\,x-{\it a1}}}+{\frac {{\it al2}\,{\it bl2}\, \left( {\it a2}\,{\it b3}-{\it a3}\,{\it b2} \right)  \left( {\it a1}\,{\it b2}-{\it a2}\,{\it b1} \right) }{{\it b2}\,x-{\it a2}}}+{\frac {{\it al3}\,{\it bl3}\, \left( -{\it a1}\,{\it b3}+{\it a3}\,{\it b1} \right)  \left( {\it a2}\,{\it b3}-{\it a3}\,{\it b2} \right) }{{\it b3}\,x-{\it a3}}} \right) }=0}
\]