title: Numpy subtraction from two arrays
body: <p>I have two numpy arrays like below</p>
  
  <pre><code>a=np.array([11,12])
  b=np.array([9])
  
  #a-b should be [2,12]
  </code></pre>
  
  <p>I want to subtract both a &amp; b such that result should [2,12]. How can I achieve this result?</p>