# Math Help - Equation that is its own inverse

1. ## Equation that is its own inverse

Why is Y = -X + B it's own inverse, I can illustrate this graphically but not algebraically. can any one help me with this??
Thank you

2. Originally Posted by i_cow044
Why is Y = -X + B it's own inverse, I can illustrate this graphically but not algebraically. can any one help me with this??
Thank you
functions are inverses if

$(f \circ f)(x)=x$ so lets try it

$(f \circ f)(x)=f(f(x))=-(-x+b)+b=x-b+b=x$

yay!!!