If $A = \begin{bmatrix} 5a & -b \\ 3 & 2 \end{bmatrix} \quad \text{and} \quad A \, \text{adj} \, A = A A^t, \quad \text{then} \, 5a + b \, \text{is equal to}$
The solution set for the inequality $ 13x - 5 \leq 15x + 4<7x + 12; x \in W $