The expression provided in the image is:

$\sqrt{x^2 + 8x - 9}$

Would you like to simplify this, solve for $x$, or explore some other aspect of the expression? Let me know what you're aiming to do!

Here are 5 related questions you might find useful:

1. How can we factor the quadratic expression inside the square root?
2. What is the domain of the function $f(x) = \sqrt{x^2 + 8x - 9}$?
3. What happens if we set $x^2 + 8x - 9 = 0$? What are the solutions for $x$?
4. Can this expression be simplified further if it represents a function?
5. How can we graph the function $f(x) = \sqrt{x^2 + 8x - 9}$?

Tip: When dealing with square roots, always consider if the expression inside the root can be factored or simplified!