\[ 3 y^{(4)}(x) y''(x)-5 y^{(3)}(x)^2=0 \] ✓ Mathematica : cpu = 0.0987539 (sec), leaf count = 28
\[\left \{\left \{y(x)\to c_2 \left (-\sqrt {2 x+3 c_1}\right )+c_4 x+c_3\right \}\right \}\] ✓ Maple : cpu = 0.812 (sec), leaf count = 28
\[ \left \{ y \left ( x \right ) =3\, \left ( {\it \_C2}+x \right ) \sqrt {6}{\it \_C1}\,\sqrt {-{\frac {{\it \_C1}}{{\it \_C2}+x}}}+{\it \_C3}\,x+{\it \_C4} \right \} \]