Respuesta :
What you do is you basically subtract the x's and y's i forget exactly how my teacher explained it but this would be how you would do it you would always have the pairs on one side like how the -16 and 19 is on one side, that's what you want.
![Ver imagen PandaLover16](https://us-static.z-dn.net/files/d43/e3d44b365819339fc7855a8ce22411aa.png)