matheme.txt

xmin = -10;
xmax = 1;
f[x_, a_] = (x + 1) a + (x + 0.7) (x + 0.2)
g[a_] :=
  (y = x  /.  Solve[f[x, a] == 0, x];
   pl1 = Graphics[{PointSize[0.02],
      Point[Table[{Re[y[[i]]], Im[y[[i]]]}, {i, 1, Length[y]}]]},
     Axes -> True, PlotRange -> {{-3, 0}, {-1, 1}}, Frame -> False,
     AspectRatio -> 1, AxesOrigin -> {0, 0}];
   pl2 = Plot[f[x, a] /. a -> 1, {x, xmin, xmax},
     PlotRange -> {{xmin, xmax}, {-3, 3}}];
   GraphicsRow[{pl1, pl2}, ImageSize -> Large])
Export["rootlocus.gif", Table[g[k], {k, 0, 7, 0.1}]