title: Confusion on the 'linear' activation in tf.keras.layers.Dense()
body: <p>In the <a href="https://www.tensorflow.org/api_docs/python/tf/keras/layers/Dense" rel="nofollow noreferrer">explanation on activation under Arguments</a>, it says </p>
  
  <blockquote>
    <p>"linear" activation: a(x) = x.</p>
  </blockquote>
  
  <p>It's confusing. Should not linear activation act like <code>wx+b</code> (if use_bias=True)?</p>