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Course 2: Inequalities. Objectives: To determine whether a number is a solution of an inequality To graph inequalities on the number line To write inequalities . Inequalities. An inequality is a mathematical sentence containing >, <, > , < . Inequalities. Inequalities.
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Course 2: Inequalities Objectives: To determine whether a number is a solution of an inequality To graph inequalities on the number line To write inequalities
Inequalities • An inequality is a mathematical sentence containing >, <, >, <.
Inequalities • Any number that makes an inequality true is a solution of the inequality. • Inequalities have many solutions. • Example: x > 4 • List 4 possible solutions. 4.5, 5, 7, 12.5
Example 2 The solutions are shown by shading a number line. Example: x > 4 3 4 5 6 7
Example 1 Determine whether each number is a solution of a) 3 yes, because 3 is less than 7 b) -2 yes, because -2 is less than 7 c) 9 no, because 9 is not less than or equal to 7 d) 7 yes, because 7 is equal to 7
1) Graph m > 3 on a number line. 1 2 3 4 5
2) Graph k < -2 on a number line. -3 -2 -1 0 1
3) Graph h > 3 on a number line. 3 4 0 1 2
4) Graph k < -2 on a number line. -3 -2 -1 0 1
Solving One-Step Inequalities by Adding or Subtracting • 1) x + 4 > 8 - 4 - 4 x > 4
Check x + 4 > 8 • Solution: x > 4 • Substitute a value that is greater than 4 for x. 5 + 4 > 8 9 > 8 This is a true statement.
Graph x > 4 1 2 3 4 5
Solving One-Step Inequalities by Adding or Subtracting • 2) c - 3 < 2 + 3 + 3 c < 5
Check c – 3 < 2 • Solution: c < 5 • Substitute a value that is less than or equal to 5 for c. 5 – 3 < 2 2 < 2 This is a true statement.
Graph c < 5 on a number line. 2 3 4 5 6
Solving One-Step Inequalities by Adding or Subtracting • 3) d - 4 < -2 + 4 + 4 d < 2
Check d – 4 < -2 • Solution: d < 2 • Substitute a value that is less than 2 for d. 1 – 4 < -2 -3 < -2 This is a true statement.
Graph d < -2. -5 -4 -3 -2 -1
Solving One-Step Inequalities by Adding or Subtracting • 4) a - 2 > 6 + 2 + 2 a > 8
Check a - 2 > 6 • Solution: a > 8 • Substitute a value that is greater than or equal to 8 for a. 8 - 2 > 6 6 > 6 This is a true statement.
Graph a > 8. 9 5 6 7 8
Solving One-Step Inequalities by Adding or Subtracting • 5) p - 7 > 0 + 7 + 7 p > 7
Check p - 7 > 0 • Solution: p > 7 • Substitute a value that is greater than 7 for p. 8 - 7 > 0 1 > 0 This is a true statement.
Graph p > 7 4 5 6 7 8
Solving One-Step Inequalities by Adding or Subtracting • 6) j + 5 < 2 - 5 - 5 j < -3
Check j + 5 < 2 • Solution: j < -3 • Substitute a value that is less than or equal to -3 for c. -3 + 5 < 2 2 < 2 This is a true statement.
Graph j < -3 on a number line. -5 -4 -3 -2 -1