algebra 1 student notes 2.1 write and graph...

Chapter 2 Solving Linear Inequalities

Algebra 1 Student Notes 1

2.1

2.1 Write and Graph InequalitiesLearning Outcomes: I can write inequalities from graphs or sentences.

I can graph inequalities.

Algebra 1 Student Notes

Sep 209:18 AM



Sep 209:21 AM

Examples:

Practice:

Sep 209:23 AM

2) Write both inequalities in set builder notation:

1)



Sep 209:24 AM

Write an inequality:1) Twice a number increased by 5 is not fewer than 10

2) Twice the sum of a number and 5 is at most 8

3) Half a number decreased by 7 is more than 20

4) Your age has to be at least 16 to get a drivers license

2.2

2.2 Solving Inequalities by Addition and Subtraction

Addition Property of Equality If a = b then a + c = b + cIf a = b then a c = b c

Addition Property of Inequalities If a > b then a + c > b + cIf a < b then a + c < b + c

Ex. 1: Solve the inequality x 5 < 9

Set builder notation:

Check the solution:

Graph the solution



Dec 49:10 AM

If a > b then a c > b cIf a < b then a c < b c

Subtraction Property of Inequalities

Ex. 2: Solve: x + 3 > 2

Ex. 3: Solve: 3 > x (5) Write all inequality solutions with the variable on the left!

Dec 49:23 AM

Inequality Verbal Expressions:Examples: A number decreased by 8 is at most 14.

A number increased by 7 is no less than 2.

You try: solve, set builder notation, graph

1. 9 < b + 4 2. t 7 > 5 3. 7 + 3 > x (4)

graphing: ________ circle for < and > ________ circle for < and >



Sep 209:51 AM

2.3

2.3 Solving Inequalities Using Multiplication and DivisionReview

6x = 18

10 > 15 10 > 15 10 > 15 10 > 15

What happens to the signs?

WARMUP:



Dec 1910:54 AM

Whenever you __________ or ________ both sides of an inequality by a ________________, then the inequality sign needs to be ________________.

Examples:

1. 2.What are we multiplying both sides by? What are we multiplying both sides by?

Dec 49:30 AM

3. 4.

5. 6. Fourfifths of a number is at most twenty. Write an inequality and solve it.

7.



2.4

2.4 Solving MultiStep Inequalities7 x + 5 = 23 verses 7x + 5 > 23

Dec 49:33 AM

a) b)

c)

Examples:



Dec 49:34 AM

d) e)Your Turn:

Dec 49:35 AM

Unique solutions.

3x + 1 = 3x + 1a) 3x + 1 < 3x + 2b)

3x + 7 < 3x + 2c) 3x + 1 < 3x + 1d)

Examples:

Your Turn:



2.5

2.5 Solving Compound Inequalities

Who likes math OR history?

Who likes math AND history?

WARMUP:

Dec 49:36 AM

Conjunction WordsOR “Union”

AND “Intersection”

(solution must work for one or the other inequality)

(solution must work for both inequalities at the same time)

How would you write the

intersection of the 2 sets:



Sep 2010:19 AM

Ex.1: Graph the solution set of y > 5 and y < 12.

Graph the solution set of y > 5 or y < 2.

Dec 49:39 AM

Ex. 2 Solve: 7 < z + 2 < 11.

Ex. 3: A ski resort has several types of hotel rooms and several types of cabins. The hotel rooms cost at most $89 per night, and the cabins cost at least $109 per night. Write and graph a compound inequality that describes the amount a guest would pay per night at the resort.



Dec 49:41 AM

4k 7 < 25 Or Ex.4

Ex. 5 graph x > 2 and x < 3

Ex. 6 graph x > 3 or x < 2

Ex. 7 graph 2 < x < 5

Dec 49:43 AM

Write the compound inequality for each.

4 2

3 8

4 2

1)

2)



2.6

2.6 Solving Absolute Value InequalitiesWarmup:

Sep 2010:41 AM

x = 3 All numbers that are 3 units from 0.

x could be ___ or ___ graph would look like

x < 3 All numbers that are within 3 units from 0. x could be _____ AND _____ graph would look like

x > 3 All numbers that are more than 3 units from 0. x could be _____ OR _____ graph would look like



Sep 2010:48 AM

x 1 < 3 All numbers that are within 3 units from 1. x could be _____ AND _____ graph would look like

Here is how you solve x 1 < 3

What is this asking: x (1) < 3

Solve and graph:

What is this asking: x + 1 < 3

Solve and graph:

Dec 168:53 AM

What is this asking: x (1) > 3Which numbers are

Solve and graph:

What is this asking: 2x 4 > 6

(Which numbers can you double and be more than ____ units from _____.)

Solve and graph:

Check that you can double the numbers graphed and the doubled value is more than 6 units from 4.



Dec 168:55 AM

Steps to solve inequalities with ABSOLUTE VALUE:A) Write the inequality without absolute value signs

B) Write again but reverse arrow and take opposite of number after the inequality sign

C) Solve and graph no solution and all numbers is a possibility

a)

b)

c)

Dec 168:57 AM

Your Turn:d) e)



Jan 31:09 PM

Write an open sentence involving absolute value for each graph below:

Sep 2011:10 AM

algebra 1 student notes 2.1 write and graph...

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