Invertible Systems
A system is invertible if distinct inputs yield distinct outputs.
Invertible System:
y(t) = $ \frac{3*x(t) + 8}{1} $
x(t) = $ \frac{y(t) - 8}{3} $
x(t) -> |Sys 1| -> y(t) -> |Sys 2| -> x(t)
The two equations are inverses of each other.
Noninvertible System:
y(t) = $ t^4 $ x(t) = $ t $ -> |Sys| -> y(t) = $ t^4 $ x(t) = $ -t $ -> |Sys| -> y(t) = $ t^4 $
The System is not invertible because for a given set of inputs you cannot differentiate which of the output will result.