1. 3-1 DAY 1 INEQUALITES & THEIR GRAPHS
Caffey
MHS Algebra I
October 2012

2. By law, the height of a newly construct4ed building in Washington DC can be no greater than the width of the adjacent street plus 20 ft. Pennsylvania street, is the widest street in DC. What is the maximum allowable height of a new building?

3. PROBLEM #1 Writing Inequalities
HOW DO YOU WRITE AN INEQUALITY?
What inequality represents the verbal expression?
All real numbers x less than or equal to -7 x
EX2: 6 less than a number k is greater than 13
k-6 >

4. Student’s Try: The sum of t and 7 is less than -3
All real numbers p greater than or equal to 1.5
The sum of t and 7 is less than -3

5. VOCABULARY
SOLUTION OF AN INEQUALITY – any number that makes the inequality true

6. PROBLEM #2 Identifying Solutions by Evaluating
Is the number a solution of 2x + 1 > -3?
The number is -3
Step 1 Write the inequality 2x + 1 > -3
Step 2 Substitute the given 2(-3) + 1 > -3
number for x
Step 3 Simplify > -3
Step 4 Compare > -3
No, Since -5 is not greater than -3, -3 is not a solution

7. TRY THIS:
Consider the numbers -1, 0, 1, and 3. Which are solutions of 13 – 7y ?

8. Determine whether each number is a solution of the given inequality
-2p – a.-2 b. 2 c. 4
a) -2 (-2) –
4 –
1 -1
This is not true, so -2 is not a solution

9. PROBLEM #2 Identifying Solutions by Evaluating
Is the number a solution of 2x + 1 > -3?
The number is -1
Step 1 Write the inequality 2x + 1 > -3
Step 2 Substitute the given 2(-1) + 1 > -3
number for x
Step 3 Simplify > -3
Step 4 Compare > -3
YES, since -1 is greater than -3, -1 IS a solution

10. HOMEWORK
PAGE 176
(7-10, EVEN)
CLOSURE: How do you decide whether a number is a solution of an inequality?
What are 3 possible values for b that make the inequality b<-4 true?

11. 3-1 Day 2 Inequalities & Their Graphs4 5 6 7 8

12. Inequalities and their Graphs
Objective: To write and graph simple inequalities with one variable

13. Inequalities and their Graphs
What is a good definition for Inequality?
An inequality is a statement that two expressions are not equal 2 3 4 5 6 7 8

14. Inequalities and their Graphs
Terms you see and need to know to graph inequalities correctly
< less than
Notice open circles
> greater than

15. Inequalities and their Graphs
Terms you see and need to know to graph inequalities correctly
≤ less than or equal to
≥ greater than or equal to
Notice colored in circles

16. Inequalities and their Graphs
Let’s work a few together
Notice: when variable is on left side, sign shows direction of solution 3

17. Inequalities and their Graphs
Let’s work a few together
Notice: when variable is on left side, sign shows direction of solution 7

18. Inequalities and their Graphs
Let’s work a few together
Notice: when variable is on left side, sign shows direction of solution
Color in circle -2

19. Inequalities and their Graphs
Let’s work a few together
Notice: when variable is on left side, sign shows direction of solution 8
Color in circle

20. Try this one on your own

21. 12

22. On your Own

23. 12

24. On your Own

25. Graphing Inequalities
Excellent Job !!! Well Done

26. PROBLEM 3: Graphing an Inequality
What is the graph of ?
***Re-Write the problem so the variable is on the left***
Step1: Since a can be
equal to 2, draw a circle at 2
Step 2: the numbers less than
2 are to the left of 2 on the
number line, so shade to the
left of 2

27. PROBLEM #4: Writing an Inequality from a Graph
L:\ALGEBRA - MHS (SANDISK)\CH 3 SOLVING INEQUALITIES (SANDISK)\3-1 DAY 2A Pearson Prentice Hall Mathematics Video.mht

28. What inequality represents the graph?
Look at the arrow – Decide if the solution is greater than or less than the endpoint
Look at the endpoint – Decide if “EQUAL TO” is included in the solution.

29. What inequality represents the graph?

30. STUDENTS TRY: 1 2

31. CLOSURE
What inequality describes the situation?

32. CLOSURE
What inequality describes the situation?

33. HOMEWORK
PAGE 181 (#5-30 ALL)