Discover Questions

Find the z-score for which the area to the right is 0.91.? I passed Chemistry because of Roger The Mole. Thanks.? How do you find the directrix and the equation given Vertex (4, 2) and Focus (4,1)?
Edit? In how many distinct ways can the letters of the word MAMASMAMAS be arranged? Are Alkai Metals or Halogens more reactive?