LU Decomposition

You're given two matrices ${\displaystyle L={\begin{pmatrix} 6 & 0 & 0 \\ 0 & 8 & 0 \\ 5 & 0 & 7 \\ \end{pmatrix}}}$ and ${\displaystyle U={\begin{pmatrix} 3 & 0 & 0 \\ 0 & 3 & 7 \\ 0 & 0 & 2 \\ \end{pmatrix}}}$. Find matrix $A$. You should write the matrix as a string of its rows in order. For example, if the matrix is ${\begin{pmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \\ \end{pmatrix}}$, then write down the following: "1 2 3 4 5 6 7 8 9". It's guaranteed that the matrix elements are whole numbers.