title: Matlab plot ax+by+c=0 when a==0 or b==0
body: <p>I am doing a sequence of arithmetic operations to determine the line equation and plot it with <code>ezplot</code>. But bad things happen when <code>a</code> or <code>b = 0</code>. I would like to save line equation with <code>0</code> in it (like <code>5*x+0*y-1=0</code>), but <code>y</code> dissapears, o find another workaround.  </p>
  
  <p><strong>Edit</strong><br>
  Here an example of my code:  </p>
  
  <pre><code>syms x y
  hold on
  for i = -1:0.5:1
      for j = -1:0.5:1
          ezplot(i*x+j*y+1, [0,10,0,10])
          pause
      end
  end  
  </code></pre>
  
  <p>I could draw lines manually when <code>a</code> or <code>b = 0</code>, but I want more general approach.</p>