TGIF: September 21, 2012

Today: Warm-Up The Real Number System Absolute Value

Class Work: Absolute Value

Note: Links to Textbooks & Workbooks should be fixed.

Warm-Up Questions

For the following, identify the Terms Like Terms Coefficients Constants

1. 2 + 6a + 4a 2. 4/7a + 3/7b + 1/5a 3. (-

2x + y)5 - 15xthen simplify where possible

Simplify the following:1. -12c + 3 - 9(11 - c) 2. -.3x - 4.2 + 6.1x - .9

Natural Numbers: {1, 2, 3, …}

Whole Numbers: {0, 1, 2, 3, …}

Integers: {…, -2, -1, 0, 1, 2, …}

Rational Numbers: Numbers expressed in the form a/b, where a and b are integers and b ≠ 0

The Real Numbers

Includes all fractions, Mixed numbers, Ratios, Proportions, & decimals.

Irrational Numbers: These numbers don't end and they don't repeat. Ex. √2, Pi,

Real Numbers

Practice: For each of the numbers, write Natural, Whole, Integer, Rational, or Real according to its type. Most will have more than one classification.

1. 0.25 2. 8.25252525 3. -1/2 4. 5 5. 0 6. -5

7. √5 8. 200 ft. below sea level

Absolute Value: |x|• An important concept in Algebra; one that you

should try to master.

Absolute Value measures the distance a number is from zero.

The following are illustrations of what absolute value means using the numbers 3 and -3:

Since Absolute Value is a measure of distance, the result can never be negative. (There can be no negative distances)

• If a number is positive (or zero), the absolute value function does nothing to it: |4| = 4

• If a number is negative, the absolute value function makes it positive: |-4| = 4

Find the value of the following: |5 + (-2)|

Did you get 7? Unfortunately, that's wrong.

If there is arithmetic to do inside the absolute value sign, you must do it before taking the absolute value sign. The correct answer is: |5 + (-2)| = |3| = 3

Absolute Value: |x|

• Simplify | 0 – 6 | 

• Simplify | 4+ (– 6)|

• Simplify | 2 – 5 |

• Simplify | 0(–4) |

• Simplify | 2 + 3(–4) |

• Simplify –| –4 |

• Simplify –| (–2)2 |

• Simplify –| –2 |2

Absolute Value: |x|

Class Work:

• Opposites & Absolute Values 1-9

• Pages 17-18, everything, including Mixed Review

• You must show all your work in order to receive credit, even if you turn in your assignment.