Hey there! I'm happy to help!
Let's look at the factors of each of these numbers.
25
1,25
5,5
30
1,30
2,15
3,10
5,6
The greatest common factor between these is 5. Therefore, we divide 25+30 by 5 and put the 5 on the outside.
5(5+6).
This has the same value but it is just written differently.
Have a wonderful day! :D