Let A = \(\begin{bmatrix} \log_5 128 & \log_4 5 \log_5 8 & \log_4 25 \end{bmatrix}\) \). If \(A_{ij}\) is the cofactor of \( a_{ij} \), \( C_{ij} = \sum_{k=1}^2 a_{ik} A_{jk} \), and \( C = [C_{ij}] \), then \( 8|C| \) is equal to:
A particle is moving in a straight line. The variation of position $ x $ as a function of time $ t $ is given as: $ x = t^3 - 6t^2 + 20t + 15 $. The velocity of the body when its acceleration becomes zero is: