The system $x' = 3 x^2 , \quad y' = 7 y^2$ has an isolated critical point at (0,0), but the system is not almost linear. Solve the system for an initial point $(x(0),y(0))= (a,b)$, where neither $a$ nor $b$ are zero (recall how to solve separable equations). Use $t$ for your time variable:
$x(t) = {}$
$y(t) = {}$

Based on this solution, the system behaves like what at the origin?
Bahavior:
Type "sink", "source", "saddle", "spiral sink", "spiral source", "center".