Answer:
Remember that in the transpose matrix of the matrix A, the entry [tex]a_{ij}[/tex] of A will be the entry [tex]a_{ji}[/tex] of [tex]A^T[/tex].
Then if
[tex]B=\left[\begin{array}{ccc}-1&1&-3\\0&2&3\end{array}\right][/tex], [tex]B^T=\left[\begin{array}{ccc}-1&0\\1&2\\-3&3\end{array}\right][/tex]
Then
[tex]B^TB=\left[\begin{array}{ccc}1&-1&3\\-1&5&3\\3&3&18\end{array}\right][/tex]
