Warm-Up Evaluate each expression, given that x=3 and y=-2. a. |2x -9| Answer: 1) -32) 33) 154) -15 b. |y –x| Answer: 1) -52) 13) -14) 5 Solve. |3x + 6| = 9 Answer: 1) x=1, -52) x= -1, 53) x= 3, -154) x= -3, 15
6.4: Absolute Values and Inequalities Objective : Learn how to solve absolute value inequalities.
Review Why is the absolute value of a number always greater than or equal to zero? Two or more inequalities connected by the words _______ or _________ are a compound inequality.
Conjunction: |a x + b| < c Means: x is between + c -c < a x +b < c Less Than when an absolute value is on the left and the inequality symbol is < or ≤, the compound sentence uses and.
Disjunction: |a x +b| > c Means: not between! a x + b c Greater Than when an absolute value is on the left and the inequality symbol is > or ≥, the compound sentence uses or.
Solving absolute inequalities and graphing: | x - 4| < 3 (less than is between) Means: -3 < x- 4 < 3 (solve) Graph: +4 1< x<
Solving absolute inequalities and graphing: |s – 3| ≤ 12 (less than is between) Means: -12 ≤ s – 3 ≤ 12 (solve) ≤ s ≤ 15 Graph:
Check Your Progress Solve each absolute value inequalities then graph. A. |y + 4| < 5 B. |z – 3| ≤ 2
Solve and graph: | x + 9 |> 13(disjunction) Means: x x < -22 x > 4 Graph:
Check Your Progress Solve each absolute value inequalities and graph. A. | 3y – 3| > 9 B. |2x + 7| ≥ 11
Change the graph to an absolute value inequality: 1. Write the inequality. (x is between) 2 < x < 8 2.Find half way between 2 and 8 It ’ s 5 (this is the median) To find the median, add the two numbers and then divide by =
3. Now rewrite the inequality and subtract 5 (the median) from each section < x - 5 < Combine like terms or numbers and you get-3 < x - 5 < 3 4. Write your absolute inequality | x - 5| < 3 Notice: The median is 3 units away from either number.
Write the inequality for this disjunction: x 4 (find the median) 2. x | x +1|>5 +1 (subtract -1 from both sides, so add 1) +1 (write x + 1 inside the absolute brackets and 5 outside positive)
Check Your Progress Write an absolute value inequality for the graph shown
Closing the lesson: Summarize the major points of the lesson and answer the Essential Question: How are absolute value inequalities like linear inequalities?
Homework: Textbook page 316 #8-30 even, 31 – 36, 38 –40