ANSWER
The value of x is
[tex]16.[/tex]
EXPLANATION
We want to solve the equation,
[tex] \sqrt{x + 9} - 4 = 1[/tex]
The first step is to add 4 to both sides of the equation to obtain,
[tex] \sqrt{x + 9} = 1 + 4[/tex]
We simplify the right hand side to obtain,
[tex] \sqrt{x + 9} = 5[/tex]
We now square both sides of the equation to obtain,
[tex] (\sqrt{x + 9} ) ^{2} = {5}^{2} [/tex]
This simplifies to
[tex] x + 9= 25[/tex]
We solve for x to obtain,
[tex]x = 25 - 9[/tex]
This implies that,
[tex]x = 16[/tex]
