first isomorphism theorem can be used.
First define a surgective map f such that
given by , where .
f is clearly surgective. Now, you need to find a kernel of f.
Since , mA is a kernel of f.
To show , you can use the above result and replace A with .
Since , you remain to show that . In a similar manner with the above, you can find a surgective map and its kernel and apply the first isomorphism theorem.