GameMaker How to bounce an object off another at an angle

[letsbenameless]

I want to maintain a similar velocity (slightly decreased) but in the opposite direction, and I want it to bounce at the angle it is relative to the larger object.
I basically just want bombs that bounce off each other in every direction and angle. The picture below shows how I want it to bounce, with the hypotenuse of this triangle representing the angle at which I want the bomb to bounce off the player if it comes close enough.

 

[obscene]

Start with this. .. https://www.gmlscripts.com/script/collision_normal

It will return the normal at the point of impact... in this case it should return 180. Then assuming your direction is something like 160 (guessing by the picture) the correct reflection angle would be 180+(180-160) or 200.