cannot be referenced from a static context

public class ClassesandObjects{
	public static void main(String[] args){
		int x = 3;
		passMethod(x);
		System.out.println("After invoking passMethod, x = " + x);
	}
	public /*static*/ void passMethod(int p){
		p = 10;
		System.out.println("Invoke passMethod, x = " + p);
	}
}

ClassesandObjects.java:4: non-static method passMethod(int) cannot be referenced
 from a static context
                passMethod(x);
                ^
1 error