Question 1121332
.
Make GOOGLE-search with keywords  "LU-factorization online calculator".


Google will show you some number of appropriate sites.


Go to any of these (of the first 3 - 5) sites.



https://keisan.casio.com/exec/system/15076953047019


http://www.gregthatcher.com/Mathematics/LU_Factorization.aspx


https://matrixcalc.org/en/



Input your matrix. Press the "Solve" button.


Get the result.