Beginning Algebra, 11th Edition

(Marvins-Underground-K-12) #1
Using the Definition of Subtraction

Subtract.


Change to.

No change Additive inverse of 3

(a)


(b) (c)


Change to.

No change Additive inverse of

(d)


(e) or 1 NOW TRY


5


6


4


3


- a-


1


2


b =


4


3


+


1


2


=


8


6


+


3


6


=


11


6


,


- 3 - 1 - 52 = - 3 + 152 = 2



  • 5








5 - 7 = 5 + 1 - 72 =- 2 - 6 - 9 = - 6 + 1 - 92 =- 15


12 - 3 = 12 + 1 - 32 = 9










EXAMPLE 6

40 CHAPTER 1 The Real Number System


NOW TRY
EXERCISE 6
Subtract.


(a)


(b)


(c) -


5

7

-

1

3

4 - 15

- 5 - 1 - 112

NOW TRY ANSWERS



  1. (a) 6 (b)


(c) - 2221 , or - 1 211


  • 11


Uses of the Symbol

We use the symbol for three purposes:


1. to represent subtraction,as in


2. to represent negative numbers,such as and


3. to represent the opposite (or negative) of a number,as in β€œthe opposite


(or negative) of 8 is ”


We may see more than one use of in the same expression, such as


where is subtracted from The meaning of the symbol depends on its


position in the expression.


- 9 - 6. -


- - 6 - 1 - 92 ,


- 8.


- 10, -2, -3;


9 - 5 = 4;


-




OBJECTIVE 4 Use the rules for order of operations with real numbers.


Adding and Subtracting with Grouping Symbols

Perform each indicated operation.


(a) Start within the innermost parentheses.


Add.
Definition of subtraction
Add.
Definition of subtraction

= 3 Add.


=- 6 + 192


=- 6 - 3 - 94


=- 6 - 32 + 1 - 1124


=- 6 - 32 - 114


- 6 - 32 - 18 + 324


EXAMPLE 7

Definition of Subtraction

For any real numbers xand y,


To subtract y from x, add the additive inverse (or opposite) of y to x .That is,


change the subtrahend to its opposite and add.


Example: 4 - 9 = 4 + 1 - 92 =- 5


xyx 1 y 2.


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