Написать программу построения графика функции (цветного)

uses graphABC;
begin
Window.Width:=500;
Window.Height:=500;
Window.Center;  
Window.Clear(clYellow);
var c:=250;
var m:=(c-20)/10;
Pen.Color:=clBlue;
Line(0,c,windowwidth,c);
Font.Color:=clBlue;
TextOut(2*c-20,c-20,'X');
Line(c,0,c,2*c);
TextOut(c+5,0,'Y');
TextOut(c+5,c+10,'0');
Pen.Width:=1;
//засечки и подписи по осям
for var i:=1 to 10 do
 begin
  Line(c+round(i*m),c-3,c+round(i*m),c+3);
  Line(c-round(i*m),c-3,c-round(i*m),c+3);
  TextOut(c+round(i*m),c+10,floattostr(i));
  TextOut(c-round(i*m),c+10,floattostr(-i));
  Line(c-5,c-round(i*m),c+5,c-round(i*m));
  TextOut(c-25,c-round(i*m)-5,inttostr(i));
  Line(c-5,c+round(i*m),c+5,c+round(i*m));
  TextOut(c-25,c+round(i*m)-5,inttostr(-i));
 end;
var x:=-10;
Pen.Color:=clRed;
Pen.Width:=2;
while x<=10 do 
 begin
  if x=-10 then MoveTo(c+round(x*m),round(c-(4*x-3)*m))
  else LineTo(c+round(x*m),round(c-(4*x-3)*m));
  x:=x+1;
 end; 
Brush.Style:=bsClear; 
Font.Color:=clRed;
Font.Size:=14;
TextOut(50,50,'y=4x-3');
end.