Question

LU Factorization of matrix A(2x2) = {1, 2}
{3, 4}
My attempts are going to be provided

Answer 1

do -3R1 + r2 to get U as {1, 2}
{0, -2}
and not I get L as {1, 0}
{-3, 1}

I know this does not come up to the original problem. Why do I need to get the inverse of L to get the correct answer?