To delete a database, you use the DROP DATABASE expression followed by the name of the database. The formula used is:

DROP DATABASE DatabaseName;

Here is an example: 

DROP DATABASE RealEstate1;
GO
To start from a sample code, open an empty Query window and display the Template Explorer. From the Template Explorer, expand Database. Drag the Drop Database node and drop it in the Query window:
-- =========================
-- Drop Database Template
-- =========================
USE master
GO

IF  EXISTS (
 SELECT name 
  FROM sys.databases 
  WHERE name = N'<Database_Name, sysname, Database_Name>'
)
DROP DATABASE <Database_Name, sysname, Database_Name>
GO
To delete a database in SQL Server Management Studio, in the Object Explorer, expand the Databases node, right-click the undesired database, and click Delete. A dialog box would prompt you to confirm your intention
If you still want to delete the database, you can click OK. If you change your mind, you can click Cancel