Answer:
Both the answers are as in the solution.
Step-by-step explanation:
As the given matrix is not in the readable form, a similar question is found online and the solution of which is attached herewith.
Part a:
Given matrix is : A = ![\left[\begin{array}{ccc}0&3&4\\1&2&3\\-3&-7&8\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%263%264%5C%5C1%262%263%5C%5C-3%26-7%268%5Cend%7Barray%7D%5Cright%5D)
Here,

Then, A is non-singular matrix.
Here, A₁₁= 0.
If we write A as LU with L lower triangular matrix and U upper triangular matrix, then A₁₁=L₁₁U₁₁.
So, As
A₁₁ = 0 gives L₁₁U₁₁= 0 ,
This indicates that either L₁₁= 0 or U₁₁ = 0.
If L₁₁= 0 or U₁₁ = 0, this would made the corresponding matrix singular, which contradicts the condition as A is non-singular.
Therefore, A has no LU decomposition.
Part b:
By the implementation of the various row operations
<em>interchange R1 and R2</em>
![\left[\begin{array}{ccc}1&2&3\\0&3&4\\-3&-7&8\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%262%263%5C%5C0%263%264%5C%5C-3%26-7%268%5Cend%7Barray%7D%5Cright%5D)
<em>R3+3R1=R3</em>
![\left[\begin{array}{ccc}1&2&3\\0&3&4\\0&-1&17\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%262%263%5C%5C0%263%264%5C%5C0%26-1%2617%5Cend%7Barray%7D%5Cright%5D)
<em>R3+(1/3)R2 = R3</em>
![\left[\begin{array}{ccc}1&2&3\\0&3&4\\0&0&55/3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%262%263%5C%5C0%263%264%5C%5C0%260%2655%2F3%5Cend%7Barray%7D%5Cright%5D)
Therefore, U =
.
Here, LP = E₁₂=E₃₁=-3 &E₃₂=-1/3
![LP=\left[\begin{array}{ccc}0&1&0\\1&0&0\\0&0&1\end{array}\right] \left[\begin{array}{ccc}1&0&0\\0&1&0\\-3&0&1\end{array}\right]\left[\begin{array}{ccc}1&0&0\\0&1&0\\0&-1/3&1\end{array}\right]](https://tex.z-dn.net/?f=LP%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%261%260%5C%5C1%260%260%5C%5C0%260%261%5Cend%7Barray%7D%5Cright%5D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260%5C%5C0%261%260%5C%5C-3%260%261%5Cend%7Barray%7D%5Cright%5D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260%5C%5C0%261%260%5C%5C0%26-1%2F3%261%5Cend%7Barray%7D%5Cright%5D)
![LP=\left[\begin{array}{ccc}0&1&0\\1&0&0\\-3&-1/3&1\end{array}\right]](https://tex.z-dn.net/?f=LP%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%261%260%5C%5C1%260%260%5C%5C-3%26-1%2F3%261%5Cend%7Barray%7D%5Cright%5D)
![LP=\left[\begin{array}{ccc}1&0&0\\0&1&0\\-1/3&-3&1\end{array}\right]\left[\begin{array}{ccc}0&1&0\\1&0&0\\0&0&1\end{array}\right]](https://tex.z-dn.net/?f=LP%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260%5C%5C0%261%260%5C%5C-1%2F3%26-3%261%5Cend%7Barray%7D%5Cright%5D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%261%260%5C%5C1%260%260%5C%5C0%260%261%5Cend%7Barray%7D%5Cright%5D)
So now U is given as
![U=\left[\begin{array}{ccc}1&2&3\\0&3&4\\0&0&55/3\end{array}\right]\\L=\left[\begin{array}{ccc}1&0&0\\0&1&0\\-1/3&-3&1\end{array}\right]\\P=\left[\begin{array}{ccc}0&1&0\\1&0&0\\0&0&1\end{array}\right]\\](https://tex.z-dn.net/?f=U%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%262%263%5C%5C0%263%264%5C%5C0%260%2655%2F3%5Cend%7Barray%7D%5Cright%5D%5C%5CL%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260%5C%5C0%261%260%5C%5C-1%2F3%26-3%261%5Cend%7Barray%7D%5Cright%5D%5C%5CP%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%261%260%5C%5C1%260%260%5C%5C0%260%261%5Cend%7Barray%7D%5Cright%5D%5C%5C)