Let \(\rm A= \begin{bmatrix}5a^2+2bc&6&8\\\\ 13&8b^2-10ac&-9\\\ -7&5&25c^2\end{bmatrix}, B=\rm \begin{bmatrix}a^2+6ab&3&5\\ 12&-b^2&6\\\ 1&4&17bc\end{bmatrix},a, b, c\in N\)
If trace (A) = trace (B) and a, b, c are sides of Δ ABC with BC = a, CA = b and AB = c, then cos A is –
1
\(-\frac{79}{120}\)
2
\(-\frac{89}{120}\)
3
\(-\frac{33}{40}\)
4
\(-\frac{31}{40}\)