On the Midterm, Question 2 states that matrix A reduces to I, the identity matrix, through row operations represented by three elimination matrices, E1, E2, E3.

We are asked to write the inverse matrix A-inverse in terms of the E's. Since A(E1)(E2)(E3) = I, can't I multiply both sides of this equation by A-inverse to yield (E1)(E2)(E3) = A-inverse?

Yet this yields the wrong answer.

Why?

Question

On the Midterm, Question 2 states that matrix A reduces to I, the identity matrix, through row operations represented by three elimination matrices, E1, E2, E3.

We are asked to write the inverse matrix A-inverse in terms of the E's. Since A(E1)(E2)(E3) = I, can't I multiply both sides of this equation by A-inverse to yield (E1)(E2)(E3) = A-inverse?

Yet this yields the wrong answer.

Why?

epoweritheta · Answer

Zcurtis , friend can you upload a screen shot of the question please so that we can understand it better