title: Mathematica: Getting rid of the "x ->" in FindInstance results
body: <p>Suppose I have the following results:</p>
  
  <pre><code>a=FindInstance[2*b^2 + b^3 == b^4 + t &amp;&amp; t &lt; 10 &amp;&amp; t &gt; -1, {b, t}, 
    Integers, 20]
  {{b -&gt; -1, t -&gt; 0}, {b -&gt; 0, t -&gt; 0}, {b -&gt; 1, t -&gt; 2}, {b -&gt; 2, 
    t -&gt; 0}}
  </code></pre>
  
  <p>How can I get rid of the "b->" and just get the array of b answers? I can get halfway there with:</p>
  
  <pre><code>a[[All,1]]
  {b -&gt; -1, b -&gt; 0, b -&gt; 1, b -&gt; 2}
  </code></pre>
  
  <p>but how can I get to just:</p>
  
  <pre><code>{-1, 0, 1, 2}
  </code></pre>
  
  <p>Thanks</p>