For some reason, the unit says "Transform' does not contain a definition for 'left'?

Question

Unity

In general, when I write player.transform.right, the code works, but when player.transform.left, for some reason, the unit writes "Transform' does not contain a definition for 'left' and no accessible extension method 'left' accepting a first argument of type 'Transform' could be found (are you missing a using directive or an assembly reference?" I am new to c#.
Here is the code:

using UnityEngine;
using System.Collections;
public class NewBehaviour : MonoBehaviour
{
    public GameObject player;
    public int speedRotation = 3;
    public int speed = 5;
    public int jumpSpeed = 50;

    void Start()
    {
        player = (GameObject)this.gameObject;
    }
    void Update()
    {

        {
            player.transform.position += player.transform.right * speed * Time.deltaTime;
        }
    }
}

Answer 1

transform.right Contains the value of the red (right) axis. To get the value of the "left" axis, you just need to take the right with a minus sign
Don't forget about the documentation: https://docs.unity3d.com/ScriptReference/Transform...