AX=B

A=LU....

NOw Here

$\begin{bmatrix} 0 &4 &3 \\ 2 &0 &-1 \\ 3&2 & 0 \end{bmatrix}$....

For finding LU decomposition of a matrix A...is possible IFF all leading det(A) must be non-zero...det(1,1) is zero...