\[ y^{(3)}(x)-\lambda y(x)=0 \] ✓ Mathematica : cpu = 0.0546754 (sec), leaf count = 53
\[\left \{\left \{y(x)\to c_1 e^{(-1)^{2/3} \sqrt [3]{\lambda } x}+c_2 e^{-\sqrt [3]{-1} \sqrt [3]{\lambda } x}+c_3 e^{\sqrt [3]{\lambda } x}\right \}\right \}\]
✓ Maple : cpu = 0.04 (sec), leaf count = 47
\[ \left \{ y \left ( x \right ) ={\it \_C1}\,{{\rm e}^{-{\frac { \left ( i\sqrt {3}+1 \right ) x}{2}\sqrt [3]{\lambda }}}}+{\it \_C2}\,{{\rm e}^{{\frac { \left ( i\sqrt {3}-1 \right ) x}{2}\sqrt [3]{\lambda }}}}+{\it \_C3}\,{{\rm e}^{\sqrt [3]{\lambda }x}} \right \} \]