\[ 4 y(x)^2 y^{(3)}(x)+15 y'(x)^3-18 y(x) y'(x) y''(x)=0 \] ✓ Mathematica : cpu = 0.115466 (sec), leaf count = 20
\[\left \{\left \{y(x)\to \frac {1}{\left (c_3 x^2+c_2 x+c_1\right ){}^2}\right \}\right \}\] ✓ Maple : cpu = 0.833 (sec), leaf count = 17
\[\left \{y \left (x \right ) = \frac {c_{3}}{\left (c_{1} \left (c_{2}+x \right )^{2}-4\right )^{2}}\right \}\]