Unexpected symbol 'Instantiate' [SOLVED]

I’m still new at c# and don’t know anything much yet, and I have facing this error saying :
'Unexpected symbol ‘Instantiate’

Here’s my entire code for now

using UnityEngine;
using System.Collections;

public class Move : MonoBehaviour {
	public float postx = 0;
	public float posty = 0;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		float posty = transform.position.y;
		float postx = transform.position.x;
	}

	
	void show(){
		Vector3 post = new Vector3(postx + 10f, 0 , Random.Range(posty + 10f, posty - 10f))
		Instantiate(prefab, post, Quaternion.identity) as GameObject;
		
	}
}

could you help me find where did I doing wrong please ?
Thanks in advance…

you’ve missed a semicolon on the previous line (#20 in your post)