title: multiply every item in a 2D list by a scalar in python
body: <p>m is a 2D matrix, something like:</p>
  
  <pre><code>[[1,2,3],[3,4,5],[6,7,1]]
  </code></pre>
  
  <p><code>print([i*5 for i in [j for j in m]])</code> does not work. It repeats items in each row 5 items. I'd like every item to be multiplies by the scalar 5. </p>
  
  <p>Don't want to use numpy. How do I solve this using list comprehensions? Thank you!</p>