title: How can I solve the linear equation xA=x which A is nonsquare
body: <p>I have a linear equation xA=b in which</p>
  
  <pre><code>A=[1/4   1/4   0    1/2
     1/3   1/3   1/3  0
     0     1/4   1/2  1/4
     1/2   0     1/4  1/4]
  </code></pre>
  
  <p>and </p>
  
  <pre><code>x=[x1 x2 x3 x4]
  </code></pre>
  
  <p>and <code>b=[x1 x2 x3 x4]</code></p>
  
  <ol>
  <li><p>How can I obtain the solution as</p>
  
  <p>x2=3/4 x1
     x3=x1
     x4=x1</p></li>
  <li><p>Add more condition that is <code>x1+x2+x3+x4=1</code>. How can I find the solution of <code>x1=4/15...</code>   </p></li>
  </ol>
  
  <p>I want to use MATLAB to solve 2 above problems? Could you suggest to me the MATLAB code to do it? Thanks </p>