Evaluate the Function f(x) = square root of x+3 at x=6

$f (x) = \sqrt{x + 3}$ at $x = 6$

Replace the variable $x$ with $6$ in the expression.

$f (6) = \sqrt{(6) + 3}$

Simplify the result.

Add $6$ and $3$ .

$f (6) = \sqrt{9}$

Rewrite $9$ as $3^{2}$ .

$f (6) = \sqrt{3^{2}}$

Pull terms out from under the radical, assuming positive real numbers.

$f (6) = 3$

The final answer is $3$ .

$3$