When sitecore 9 using new Azure setup has been installed there are 5 different database servers. I want to know why we have different database for Forms and individual database servers. Also I am unable to connect to this database via MS-SQL.
In the image you provided, there is only a single server. There are 4 databases that will run on that server.
In your picture, you have the Core DB, Forms DB, Master DB, and Web DB all running on the 'sitecore9-isobar-261150-sql' server.
If you are used to running locally, you might be familiar with SQL Server Management Studio. This would be similar to connecting to Management Studio on the single server (your laptop/desktop) and then seeing 4 databases listed that you can browse.
You may wish to look at the Azure SQL documentation for more information: https://docs.microsoft.com/en-us/azure/sql-database/sql-database-servers-databases
A single database created within an Azure resource group with a combined set of compute and storage resources or an independent scale of compute and storage resources. An Azure SQL database is associated with an Azure SQL Database logical server, which is created within a specific Azure region.