inverse equation
posted by Ali .
How is any equation of the form y= x + b its own inverse?

write it as
x + y = b
now recall how you take the inverse.
Isn't your first step simply to switch around the x and y variables?
So what you you get ? 
The same equation, just simply switched:
if you have
x+y= b, the inverse is y+x=b, which is the same thing and therefore its own inverse?
Thank you!