## Intermediate Algebra (6th Edition)

We are given that $f(x)=\sqrt(x+2)$ is a one-to-one function. Also we know that the inverse of a one-to-one function $f$ is the one-to-one function $f^{-1}$ that consists of the set of all ordered pairs $(y,x)$ where $(x,y)$ belongs to $f$. From 16a, we know that $f(-1)=1$, which means that $f$ consists of the ordered pair $(-1,1)$. Therefore, (1,-1) must be a part of $f^{-1}$. Therefore, $f^{-1}(1)=-1$.