how do I find the inverse of the first function ?

[tex]\boxed{\boxed{\pink{\sf \leadsto Hence \ the \ Inverse \ of \ the \ given \ function \ is \ x^2+2x-4 .}}}[/tex]
A function is given to us , and we need to find its inverse. So the function is ,
[tex]\bf\implies f(x) = \sqrt{x + 5 } - 1 [/tex]
So , firstly replace x with y in the given function and then solve for y to get its inverse . Taking the given function ,
[tex]\bf \implies f(x) = \sqrt{x+5}-1\\\\\bf\implies y = \sqrt{x+5}-1 \\\\\bf\implies x = \sqrt{y+5}-1 \:\:\bigg\lgroup \red{\sf Replacing \ x \ with \ y .} \bigg\rgroup \\\\\bf\implies x + 1 = \sqrt{y+5}\\\\\bf\implies y+5 = (x+1)^2 \\\\\bf\implies y+5 = x^2+1 +2x \\\\\bf\implies y = x^2+1-5+2x \\\\\bf\implies y = x^2-4+2x \\\\\bf\implies \boxed{\red{\bf f^{-1}(x)= x^2+2x - 4 }}[/tex]
Here I have also attached the graph of , x² + 2x - 4 and √(x+5) - 1. Here blue graph is of √(x+5) - 1 & red of x²+2x-4.