The Centers for Disease Control and Prevention (CDC) is recognized as the lead United Statesagency[?] for protecting the health and safety of people by providing credible information to enhance health decisions, and promoting health through strong partnerships. CDC serves as a national focus for developing and applying disease prevention and control (especially infectious diseases), environmental health[?], and health promotion[?] and education[?] activities designed to improve the health of the people of the United States.
... is not 2. (In a field of characteristic 2, the element 2a is zero and it is impossible to divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in ...