test

$$\begin{array}{r}{\mathbf{X}}^{\mathrm{\top }}=\left[\begin{array}{rrrr}2& 6& 5& 1\\ -2& 6& 4& -7\\ -8& -4& 3& 6\\ 6& 9& -7& 7\\ -7& 6& 8& -1\end{array}\right]\end{array}$$