Determine the following elementary matrices and their inverses. URGENT

Question

No one answered my question the other time I posted. I'm not sure why I'm getting this question wrong. I have one last attempt. Please help asap! Here's the link to part 1: https://ibb.co/mGkztbL

And here's the link to part 2: https://ibb.co/z54SJ31

Answer 1

Elementary matrices always have a determinant of 1 or -1. You are providing the product EA. The question is what is the matrix E such that EA results in A having the first row multiplied by 1/2. Your answer should be

[1/2 0

0 1]

Here when you left multiply E to A, the 1/2 will multiply by the first row. The 0,1,0 make sure the rest of the matrix is left alone.