Let $ a,b$ be integers greater than $ 1$. What is the largest $ n$ which cannot be written in the form $ n \equal{} 7a \plus{} 5b$ ? 

$\textbf{(A)}\ 82  \qquad\textbf{(B)}\ 47  \qquad\textbf{(C)}\ 45  \qquad\textbf{(D)}\ 42  \qquad\textbf{(E)}\ \text{None}$
1. **Expressing \(a\) and \(b\) in terms of non-negative integers:**
   Given \(a\) and \(b\) are integers greater than 1, we can write \(a = 2 + x\) and \(b = 2 + y\) where \(x, y \geq 0\).

2. **Substituting \(a\) and \(b\) into the given form:**
   \[
   n = 7a + 5b = 7(2 + x) + 5(2 + y) = 7 \cdot 2 + 7x + 5 \cdot 2 + 5y = 14 + 10 + 7x + 5y = 24 + 7x + 5y
   \]

3. **Identifying the largest number that cannot be expressed as \(7x + 5y\):**
   The largest number that cannot be expressed as \(7x + 5y\) for non-negative integers \(x\) and \(y\) is given by the Frobenius number for the pair (7, 5). The Frobenius number \(g(a, b)\) for two coprime integers \(a\) and \(b\) is:
   \[
   g(7, 5) = 7 \cdot 5 - 7 - 5 = 35 - 12 = 23
   \]

4. **Adding the constant term to the Frobenius number:**
   Since \(n = 24 + 7x + 5y\), the largest number that cannot be written in this form is:
   \[
   23 + 24 = 47
   \]

Conclusion:
\[
\boxed{47}
\]