> f:=(x,y)->-x^3/3-x*y-y^2+x+3/2;

                                   3          2
             f := (x, y) -> - 1/3 x  - x y - y  + x + 3/2

> with(plots): delta:=.05 ;

                             delta := .05

> 

                             1.104563176

> i:=1;x[i]:=0.9;y[i]:=delta+fsolve(f(x[i],'y[i]')=0,'y[i]'=0..2);t[i]:=`0m`;

                                i := 1


                              x[1] := .9


                         y[1] := 1.136066405


                              t[1] := 0m

> i:=3;x[i]:=0.9;y[i]:=delta+fsolve(f(x[i],'y[i]')=2,'y[i]'=-0.5..2);t[i]:=`200m`;

                                i := 3


                              x[3] := .9


                         y[3] := .1995831886


                             t[3] := 200m

> i:=2;x[i]:=0.9;y[i]:=delta+fsolve(f(x[i],'y[i]')=1,'y[i]'=0..2);t[i]:=`100m`;

                                i := 2


                              x[2] := .9


                         y[2] := .7659759860


                             t[2] := 100m

> i:=4;y[i]:=0.6;x[i]:=-delta+fsolve(f('x[i]',y[i])=2,'x[i]'=-2..0);t[i]:=`200m`;

                                i := 4


                              y[4] := .6


                         x[4] := -1.709675026


                             t[4] := 200m

> for i from 1 to 3 do p[i]:=textplot([x[i],y[i],t[i]],align=ABOVE,font=[TIMES,BOLD,10]):
> od; i:=4;
> p[i]:=textplot([x[i],y[i],t[i]],align=LEFT,font=[TIMES,BOLD,10]):

  p[1] := PLOT(TEXT([.9, 1.136066405], 0m, ALIGNABOVE),

        FONT(TIMES, BOLD, 10))


  p[2] := PLOT(TEXT([.9, .7659759860], 100m, ALIGNABOVE),

        FONT(TIMES, BOLD, 10))


  p[3] := PLOT(TEXT([.9, .1995831886], 200m, ALIGNABOVE),

        FONT(TIMES, BOLD, 10))


                                i := 4

> g:=0.4;q:=contourplot(f,-2..3,-3..2,contours=[seq(0.25*i,i=0..10)],grid=[100,100],color=COLOR(RGB,g,g,g)):
> 

                               g := .4

> q2:=contourplot(f,-2..3,-3..2,contours=[seq(i,i=0..2)],grid=[100,100],color=black,thickness=3):
> 
> display({q,q2,seq(p[i],i=1..4)},axes=boxed,scaling=constrained);

>