Radicals
Table for a square root function

Fill in the table using this function rule.
\[
f(x)=\sqrt{x}-2
\]

Simplify your answers as much as possible.
Click "Not a real number" if applicable.
\begin{tabular}{|c|c|}
\hline$x$ & $f(x)$ \\
\hline-4 & $\square$ \\
\hline 0 & $\square$ \\
\hline 49 & $\square$ \\
\hline 81 & $\square$ \\
\hline
\end{tabular}

Step 1 ：The function rule is \(f(x)=\sqrt{x}-2\). We will use this rule to find the values of \(f(x)\) for each given \(x\).

Step 2 ：When \(x=-4\), we have \(f(-4)=\sqrt{-4}-2\). But the square root of a negative number is not a real number. So, \(f(-4)\) is not a real number.

Step 3 ：When \(x=0\), we have \(f(0)=\sqrt{0}-2=0-2=-2\).

Step 4 ：When \(x=49\), we have \(f(49)=\sqrt{49}-2=7-2=5\).

Step 5 ：When \(x=81\), we have \(f(81)=\sqrt{81}-2=9-2=7\).

Step 6 ：So, the completed table is: \begin{tabular}{|c|c|} \hline \(x\) & \(f(x)\) \\ \hline -4 & Not a real number \\ \hline 0 & \(-2\) \\ \hline 49 & \(\boxed{5}\) \\ \hline 81 & \(\boxed{7}\) \\ \hline \end{tabular}