Matrix dimensions must agree

Hi, I am having trouble with solving a system of linear equations. I am getting an error that the matrix dimensions must agree and i cannot divide a/b.

if true
  x1=167.48;
x2 = 355.63;
x3 = 355.63;
x4=264.58;
x5=62.93;
x6=167.48;
a= 1000.*(6+.005.*x1)./1.1 ;
b= 1000.*(6+.005.*x2)./1.1 ;
c= 1000.*(6+.005.*x3)./1.1 ;
d= 1000.*(6+.005.*x4)./1.1 ;
e= 1000.*(6+.005.*x5)./1.1;
f= 1000.*(6+.005.*x6)./1.1;
g= (1000.*(6+.005.*x1)/1.1).^-1;
h= (1000.*(6+.005.*x2)/1.1).^-1;
i= (1000.*(6+.005.*x3)/1.1).^-1;
j=(1000.*(6+.005.*x4)/1.1).^-1 ;
k=(1000.*(6+.005.*x5)/1.1).^-1;
l=(1000.*(6+.005.*x6)/1.1).^-1 ;
r = -.0024
a = [1,0,0,0,0,0,       0,0,0,0,0,0,    g,0,0,0,0,0     0,0,0,0,0,0;
   0,1,0,0,0,0,       0,0,0,0,0,0,    0,h,0,0,0,0     0,0,0,0,0,0;
   0,0,1,0,0,0,       0,0,0,0,0,0,    0,0,i,0,0,0     0,0,0,0,0,0;
   0,0,0,1,0,0,       0,0,0,0,0,0,    0,0,0,j,0,0     0,0,0,0,0,0;
   0,0,0,0,1,0,       0,0,0,0,0,0,    0,0,0,0,k,0     0,0,0,0,0,0;
   0,0,0,0,0,1,       0,0,0,0,0,0,    0,0,0,0,0,l     0,0,0,0,0,0;

     r,0,0,0,0,0        1,0,0,0,0,0     0,0,0,0,0,0     0,0,0,0,0,0;
     0,r,0,0,0,0        0,1,0,0,0,0     0,0,0,0,0,0     0,0,0,0,0,0;
     0,0,r,0,0,0        0,0,1,0,0,0     0,0,0,0,0,0     0,0,0,0,0,0;
     0,0,0,r,0,0        0,0,0,1,0,0     0,0,0,0,0,0     0,0,0,0,0,0;
     0,0,0,0,r,0        0,0,0,0,1,0     0,0,0,0,0,0     0,0,0,0,0,0;
     0,0,0,0,0,r        0,0,0,0,0,1     0,0,0,0,0,0     0,0,0,0,0,0;

     0,0,0,0,0,0        a,0,0,0,0,0     0,0,0,0,0,0     1,0,0,0,0,0;  
     0,0,0,0,0,0        0,b,0,0,0,0     0,0,0,0,0,0     0,1,0,0,0,0; 
     0,0,0,0,0,0        0,0,c,0,0,0     0,0,0,0,0,0     0,0,1,0,0,0; 
     0,0,0,0,0,0        0,0,0,d,0,0     0,0,0,0,0,0     0,0,0,1,0,0;
     0,0,0,0,0,0        0,0,0,0,e,0     0,0,0,0,0,0     0,0,0,0,1,0;
     0,0,0,0,0,0        0,0,0,0,0,f     0,0,0,0,0,0     0,0,0,0,0,1; 

     0,0,0,0,0,0        0,0,0,0,0,0     0,0,0,0,0,0     1,0,0,0,0,-1;
     0,0,0,0,0,0        0,0,0,0,0,0     0,0,0,0,0,0     0,1,0,0,0,-1;
     0,0,0,0,0,0        0,0,0,0,0,0     0,0,0,0,0,0     0,0,1,0,0,-1;
     0,0,0,0,0,0        0,0,0,0,0,0     0,0,0,0,0,0     0,0,0,1,0,-1;
     0,0,0,0,0,0        0,0,0,0,0,0     0,0,0,0,0,0     0,0,0,0,1,-1;
     0,0,0,0,0,0        0,0,0,0,0,0     1,1,1,1,1,1     0,0,0,0,0,0;];
 %   1  2 3 4 5 6 7 8 9 101112131415161718192021222324
 b = [0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;];
 x= size(a)   
 z = size(b)
 y = a/b
  end

Answer 1

[KSSV]

Replace:

   y = a/b

with

   y = a\b