To solve this problem follow the steps below.
Step 1:List out all of the factors for -36
-36: 1,2,3,4,6,9,12,18,36
-1,-2,-3,-4,-6,-9,-12,-18,-36
Step 2: Start going through a process of guessing and checking (basically take any two factors and add them together to see if they equal 13)
1 plus 12=13
9 plus 4=13
Step 3:Check your calculations and make sure you didn't make any errors
13-12=1 and 13-1=12
13-9=4 and 13-4=9
Answer: 1 and 12
4 and 9
I hope this helps and if any false information was given I apologize in advance.