\[ \left \{a y'(t)+t x'(t)-x(t)+y'(t)^2=0,x'(t) y'(t)+t y'(t)-y(t)=0\right \} \] ✓ Mathematica : cpu = 0.0168313 (sec), leaf count = 31
\[\left \{\left \{x(t)\to a c_2+c_1 t+c_2{}^2,y(t)\to c_2 t+c_1 c_2\right \}\right \}\] ✓ Maple : cpu = 0.274 (sec), leaf count = 194
\[\left [\left \{x \relax (t ) = -\frac {t^{2}}{3}\right \}, \left \{y \relax (t ) = -\frac {t^{3}}{27 a}\right \}\right ]\]