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Linear Algebra

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2x2 PLU factorization

LINALG-IXEWBB

Suppose:

$$\begin{pmatrix}0&-1\\\ 1&0\end{pmatrix}=PLU$$

...is a PLU factorization (LU with partial pivots).

If:

$$U=\begin{pmatrix}5&0\\\ 0&5\end{pmatrix}$$

...then what is $L$?

A

$\begin{pmatrix}1&0\\\ 0&1\end{pmatrix}$

B

$\begin{pmatrix}-1&0\\\ 0&1\end{pmatrix}$

C

$\begin{pmatrix}\cfrac{1}{5}&0\\\ 0&\cfrac{1}{5}\end{pmatrix}$

D

$\begin{pmatrix}-\cfrac{1}{5}&0\\\ 0&\cfrac{1}{5}\end{pmatrix}$

E

Not enough information given.