Prove that `.^(n-1)C_(3)+.^(n-1)C_(4) gt .^(n)C_(3)` if `n gt 7`.

Explanation

To prove that \( \binom{n-1}{3} + \binom{n-1}{4} > \binom{n}{3} \) for \( n > 7 \), we can use the properties of combinations.

### Step-by-Step Solution:

1. **Start with the left-hand side:**
\[ \binom{n-1}{3} + \binom{n-1}{4} \]
...