Inequalities & Graphical Inequalities

• >

  Greater than
• <

  Less than
• Whenever you multiply/divide by a negative number in an inequality you must what?

  Reverse the inequality sign.
• What represents greater than or less than on a number line?

  An open circle.
• What represents greater than or equal to or less than or equal to on a number line?

  A closed circle.
• If x2 > a2 then > a or x > -a.
• If x2 < a2 then -a < x < a.
• The four steps to showing inequalities on a graph:

  1. Convert each inequality to an equation. (sign turns to =)
  2. Draw the graph for each equation (dotted line for no equals to, solid line if there is equals to present)
  3. Work out which side of each line you want (put a point, usually the origin, into the inequality to see if its on the correct side)
  4. Shade the region this gives you.