To subtract the square roots \( \sqrt{823} - \sqrt{23} \), we can simplify or approximate each term, but we cannot directly subtract the square roots without either approximating or finding a common factor.
However, none of the choices provided seem to be a direct simplification of \( \sqrt{823} - \sqrt{23} \). So let's analyze the closest simplification:
-
Approximate \( \sqrt{823} \):
- The approximate value of \( \sqrt{823} \) is about \( 28.7 \).
-
Approximate \( \sqrt{23} \):
- The approximate value of \( \sqrt{23} \) is about \( 4.8 \).
So performing the subtraction: \[ \sqrt{823} - \sqrt{23} \approx 28.7 - 4.8 \approx 23.9. \]
Now, check the provided options to see if they provide an approximate that aligns:
- \( \sqrt{746} \) is about \( 27.4 \) and is not close.
- \( \sqrt{723} \) is about \( 26.9 \) and is not close.
- \( \sqrt{823} \) is not a subtraction, it is the original term.
None of the answers seems to be right, as they do not match \( \sqrt{823} - \sqrt{23} \) directly.
Thus, we determine that \( \sqrt{823} - \sqrt{23} \) does not match any of the responses. Please verify or provide additional information for clarity.