Q:

Indexing an array in MATLAB

So I have two matrices A= [3;0;0;0;0;0;0]; and B is 7x7 matrix, so I got it to print all the values of this system equation. 
Now, what I need help with is how can I get it to take the first answer and then divide it by the first value in matrix A.
This is my code:-
format longE
A= [3E-3;0;0;0;0;0;0]; 
B= [2.303E3 -1E3 0 -1E3 0 0 0;
    -1E3 2.5E3 -1E3 0 -500 0 0; 
    0 -1E3 2.303E3 -1E3 0 -303.03 0;
    -1E3 0 -1E3 3E3 0 0 -1E3; 
    0 -500 0 0 2E3 -500 0; 
    0 0 -303.03 0 -500 1.803E3 -1E3; 
    0 0 0 -1E3 0 -1E3 2.5E3]; 
x=B\A

So if you run this code, it will print 7 numbers.
I would like to know how I can take only the first number that it prints and then divide it by 3, which is the first number from matrix A

A:

You can index arrays in this way:
value = x(1)/A(1)

By the way A(1) is not 3, but 0.003

