<< Graphics`ImplicitPlot`

<< Graphics`Graphics`

ConstrainedMin[
      2 x - 3 y, {x + y < 10, x - y > 2, x > 1}, {x, y}]

LinearProgramming[{2, -3},(({{-1, -1}, {1, -1}, {1, 0}})),{-10, 2, 1}]

fce = x^3 + x*(y^2);
podminka =  .02*x^3 + 0.05*(x^2)*y + (y^2) - 
          6;
ImplicitPlot[podminka == 0, {x, -5, 45}]

lagrange = fce + λ*podminka;
res = 
        Solve[{D[lagrange, x] == 0, D[lagrange, y] == 0, 
              podminka == 0}] // N;

data = Select[{x, y} /. res, #[[1]] ∈ Reals &]

DisplayTogether[ImplicitPlot[podminka == 0, {x, -20, 45}], 
      ListPlot[data, PlotStyle -> {Hue[0], PointSize[ .03]}]]