To find an expression that has the same sum as \(-15 + 6\), we first calculate that sum:
\[ -15 + 6 = -9 \]
Now we need to evaluate the provided responses to see which one also equals \(-9\):
- \(15 + 6 = 21\)
- \(15 + (-6) = 9\)
- \(15 + (-6) = 9\) (duplicate of the previous)
- \(-6 + (-15) = -21\)
- \(-6 + (-15) = -21\) (duplicate of the previous)
- \(6 + (-15) = -9\)
Thus, the expression that has the same sum as \(-15 + 6\) is:
\[ 6 + (-15) \]
So, the correct response is \(6 + (-15)\).