Use the triangle inequality to show that if a and be are in R, with a not equal to b, then there exists an open interval U centered at a and V centered at b, both of radius epsilon= 1/2 abs[a-b] , with U/\V= 0 (intersection)

I really don't know what I wanna do here. I'm imagining a line centered at A and another at b with radius epsilon something like this =>

----- (-e)-------a-------(e)------

-----(-e)--------b-------(e)-----