Ungleichungssysteme mit JavaScript

<script language="JavaScript">
var x,y,xmin=0,xmax=0,ymin=0,ymax=0,min=1000,max=-1000;
for (x=0;x<=20;x++)
  for (y=0;y<=20;y++)
    if ((x+y<10) && (y >=x+2)) 
	  { if ((7*x+5*y+3) > max) { max=7*x+5*y+3; xmax=x; ymax=y };
	    if ((7*x+5*y+3) < min) { min=7*x+5*y+3; xmin=x; ymin=y } }
document.write("7*",xmax,"+5*",ymax,"+3 = ",max,"<br>");
document.write("7*",xmax,"+5*",ymax,"+3 = ",max,"<br>");
</script>