# Finding elementary matrices E1 and E2 such that: B = E1E2A, confused!

1. Oct 30, 2005

### mr_coffee

Hello everyone, i've been searching in this book forever to find an example but no luck. My problem states:
Find two Elementary matrices E1 and E2 such that $$B = E_2E_1A$$
A =
2 3
-1 8

B =
1 11
3 -24

Can someone explain to me what they want me to do?
The books says:
A -> E1A->E2E1A -> Ek .... E2E1A;
Ei denote the elementary matrix corresponding to the ith row operation. and suppose that a series of k elementary row operations is applied to an arbitrary matrix A.

THanks!

2. Oct 31, 2005

### CarlB

Staring at the matrices for a moment makes it clear that the two row operations they want are:

(1) Add the second row to the first row.
(2) Multiply the second row by -3.

Can you write down these matrices?

Carl