Let's solve each expression step-by-step:
1. \( (9r - 5) - (-4r + 9) \)
\[ = 9r - 5 + 4r - 9 \]
\[ = 13r - 14 \]
2. \( (3b - 4) - (-5b + 3) \)
\[ = 3b - 4 + 5b - 3 \]
\[ = 8b - 7 \]
3. \( (-4k - 1) - (-6k - 6) \)
\[ = -4k - 1 + 6k + 6 \]
\[ = 2k + 5 \]
4. \( (-6k + 7) - (7k + 4) \)
\[ = -6k + 7 - 7k - 4 \]
\[ = -13k + 3 \]
5. \( (5k - 6) - (k - 4) \)
\[ = 5k - 6 - k + 4 \]
\[ = 4k - 2 \]
6. \( (-6x - 8) - (8x - 9) \)
\[ = -6x - 8 - 8x + 9 \]
\[ = -14x + 1 \]
7. \( (3f + 7) - (-5f + 4) \)
\[ = 3f + 7 + 5f - 4 \]
\[ = 8f + 3 \]
8. \( (-6k - 4) - (-3k - 4) \)
\[ = -6k - 4 + 3k + 4 \]
\[ = -3k \]
9. \( (7c + 2) - (-3c + 4) \)
\[ = 7c + 2 + 3c - 4 \]
\[ = 10c - 2 \]
10. \( (-4f + 5) - (f + 3) \)
\[ = -4f + 5 - f - 3 \]
\[ = -5f + 2 \]
These are the simplified forms of each given expression.
