The equivalent system obtained by performing the interchange of equation 1 and 3 is presented as follows;
6·x - 6·y + 4·z = 1...(3)
x - 9·z = 6...(2)
8·x - 9·y + 7·z = 2...(1)
9·x - 3·y + 2·z = 5...(4)
An elementary operation consists of the following operations
Interchanging the order of listing of the system of equations
The multiplication of any of the equations within the system of equation by constant which is a non zero number
Replacement of any equation with an equation consisting of itself added to another member of the system of equations multiplied by a value which is a non zero number