Answer:
-3
Explanation:
A method you could've used is to guess and check where you use a number and check it to see if it works. Also you could've divided without the negative sign and then add it in the end. Then check it doing the inverse operation, which is multiplication, to see if it's correct.
For example:
Let's say that we're gonna use -3 to guess and see if we get one of the other numbers.
-3 · 12 = ?
You'd check that to see if it equals -36, and you can use as many numbers as you'd like until you get the answer.
I hope that helps! Have a great day!