Reading in x

import java.util.Scanner;

class EvalPoly
{
  public static void main (String[] args )  
  {
    Scanner scan = new Scanner ( System.in );

    double x;                      // a value to use with the polynomial
    String response = "y";         // "y" or "n"

    while ( response.equals( "y" ) )    
    {
       // Get a value for x.
       System.out.println("Enter a value for x:") ;
       x = scan.;

       // Evaluate the polynomial.

       // Print out the result.

       // Ask the user if the program should continue.
       System.out.println("continue (y or n)?");
       response = scan.next();      
    }

  }
}