To subtract \(\sqrt{823} - \sqrt{23}\), we can rewrite it as follows:
\[ \sqrt{823} = \sqrt{23 \cdot 36} = \sqrt{23} \cdot \sqrt{36} = 6\sqrt{23} \]
Now, substituting this back into the expression:
\[ \sqrt{823} - \sqrt{23} = 6\sqrt{23} - 1\sqrt{23} = (6 - 1)\sqrt{23} = 5\sqrt{23} \]
However, upon checking the available options again, it seems I misunderstood your request earlier. You asked for a direct subtraction of the roots.
Let’s subtract \(\sqrt{823} - \sqrt{23}\) directly without grouping:
\[ \sqrt{823} - \sqrt{23} \]
This is still left in its simplest form, as we cannot combine these two surds further without an approximation. The result won't match any options provided.
So, according to the options provided earlier, none of them represent the result \(\sqrt{823} - \sqrt{23}\) or \( \sqrt{23}(6 - 1) = 5\sqrt{23}\), as those terms would not simplify to match any provided responses.
If you need one of the provided options as the closest response, can you clarify or double-check the options?