What is the inverse of f(x)=x^2+5 and is it a function?

hello :

let : y = f(x)

you have : y = x² + 5

calculate : x

x² =  y - 5

x  exsit for : y - 5 ≥ 0

if : x  ≥ 0    x = √( y - 5)  so the inverse functio for f is : g(x) = √( x - 5)

if : x  ≤ 0    x = - √( y - 5)  so the inverse functio for f is :h(x) = -  √( x - 5)

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