Respuesta :

The answer is A.

You put the numbers in order of the letters and if a letter is missing you put 0

Answer:

A)  x + 2y = 4

3x + 4y -9z = 2

-x + 7z = 1

Step-by-step explanation:

The matrix form is

x y z  

1 2 0    4

3 4 -9   2

-1 0 7    1

Here 0 represents no term in system.

So, the following system represents the above matrix.

x + 2y + 0z = 4  => x + 2y = 4

3x + 4y -9z = 2

-x + 0y + 7z = 1  => -x + 7z = 1

Therefore, the answer is A.