What are all values of x such that  x2 + 7 x + 6 ≥ 0 ?
  1. -6 ≤ x ≤ -1
  2. -6 ≤ x ≤ 1
  3. 1  ≤ x ≤ 6
  4. x ≤ -6   or   x ≥ -1
  5. x ≤ 1   or   x ≥ 6