title: Solving unknowns of a matrix in Matlab
body: <p>I have a list of formula stored in a cell array, and I solve the unknowns within the matrix.</p>
  
  <pre><code>For example, consider a 2*2 matrix:
  [2x+y, 4q+z; 3x+0.5y, 2q+12z ]
  </code></pre>
  
  <p>How to solve q,x,y,z by setting each cell equals 20? (i.e., q= 4, x =5, y = 10, z=1)</p>