25 setxunit
7.5 setborder
90 setangle_repere
-3 5 setxrange
-4 8 setyrange
1 1 settkstep
.5 .5 setsubtkstep
2 2 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
unites
/f {setxvar
#rpn#   x^3-6*x^2+9*x
} def
/g {setxvar
#rpn#   8-3*x
} def
gsave
   bleu
   .75 setlinewidth
   continu
   {f} courbe
grestore
gsave
   rouge
   .75 setlinewidth
   mixte
  xmin  .01 neg {g} Courbe
  .01  xmax {g} Courbe
grestore