How to create a Graph in Unity

Hi I'm trying to make a graphing calculator in Unity. I have it so that the code would instantiate an object throughout the course of the graph. I realize I could use a particle system to achieve the same effect but for this project I have to do this in this way or some similar form.

 using UnityEngine;
 using System.Collections;
 
 public class Graph : MonoBehaviour
 {
     public Rigidbody GraphPointPrefab;
     public int Resolution = 100;
     private int i = -20;
     private float Xposition = -20;
     private float Yposition = 1;
 
     void Update () 
     {
         while (i <= Resolution) 
         {
             Yposition = 2 * Xposition +3;//equation
 
             Instantiate (GraphPointPrefab, new Vector3 (Xposition, Yposition), Quaternion.Euler(0, 0, 0));
 
             Xposition = + 1;
 
 
 
             i ++;
         }
     }
 }