How to form three magic squares using both negative and positive numbers without repeating any number?

A magic square consists of distinct integers such that the sum of integers in any horizontal ,vertical or main diagonal is always the same magic constant.

Two such magic squares consisting of  distinct positive and negative integers are shown below:-


Now the question arises how to form a magic squares.
Let us discuss that 
The figure shown below represents a magic square where a,b,c are integers 

Hence putting the values of a,b and c ,you can easily form a magic square ​and if  c$\ne$2b then you will get a magic square consisting of distinct integers