how to solve question 10

Answer:
Option E [tex]x=x^2-10x+21[/tex]
Step-by-step explanation:
we have
[tex]x-5=\sqrt{x+4}[/tex]
we know that
For x> 5 both sides of the equation will be positive
Squared both sides
[tex](x-5)^2=(\sqrt{x+4})^2[/tex]
[tex](x-5)^2=(x+4)[/tex]
[tex]x^2-10x+25=(x+4)[/tex]
Subtract 4 both sides
[tex]x^2-10x+25-4=(x+4)-4[/tex]
[tex]x^2-10x+21=x[/tex]
Rewrite
[tex]x=x^2-10x+21[/tex]