2-5 hw = pg. 99- 101 #6-50 e, 56-57. 2-5 hw continued 56.) c57.) b
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2-5 HW = Pg. 99- 101 #6-50 e, 56-57
2-5 HW Continued
56.) C 57.) B
Quiz 2 #1-12
Wir2.5• LESSON
Reciprocal = the flip of a fraction or whole number so that the product of a number and it’s reciprocal is 1.
- called Inverse Property of Multiplication
- the reciprocal of a is when
- the reciprocal of
Division Rule = to divide (find the quotient) a number a by a nonzero number b, multiply a by the reciprocal of b
-
2-6 Division of Real Numbers
1
a0a
b as long as a 0 or b 0
a
ais
b
1 1 1 -1 3=-1
3 3a b a
b
Another way to look at division of fractions:
• Try to make the denominator a WHOLE #.• Whatever you do to the DENOMINATOR
you MUST do to the NUMERATOR.Examples:
5 5 5 2 5 29 91.) 2.
7)
2 297
9 99
Answers:
5
9
9
2
99
5
9
5
2
95
189
7
2
7
7
7
3
18
5
Sign of a quotient
• Same signs: (-)/(-) = + or (+)/(+)=+– take quotient of absolute values– answer is POSITIVE
• Different signs: (-)/(+) = - or (+)/(-) = -– take quotient of absolute values– answer is NEGATIVE
PracticeFind the quotient.
:
11.) 7 7 2 14
21
2.) 10 (- ) 10 ( 5) 505
3.) -12 3 = -4
16 9 94.) 16 8 72
-2 2 1936 6 216 1
5.) 36 435 5 5 56
3 5 56.) -87 (- ) 87 29 145
5 3 1
Answers
11.) 7
21
2.) 10 (- )5
3.) -12 3
164.)
-2936
5.) 56
36.) -87 (- )
5
Practice 2Simplify the expression
2
11.) 6t (- )
2x
2.) - 312
3y 13.)
4 23
4.) 33x11
45.) 8x ( )
52w
6.) -7 (- )-7
2 2 2 2
Answers:
11.) 6t (- ) = 6t (-2) = -12t
2x 1
2.) - 312 12 3 36
3y 1 3 33.) 2
4 2 4 23 11
4.) 33x 33 11 11 12111 3
4 55.) 8x ( ) 8 ( ) 2 5 10
5 42w
6.) -7 (- ) 2-7
x x
y y
x x x
x x x
w
Practice 3Evaluate the expression
2
3r-71.) when r = 7
11
15x 10 22.) when x = -3 and y =
y 3
3a-4b 1 13.) when a = - and b =
ab 3 4
2
Answers:
3(17)-7 51-7 441.) = 4
11 11 11
15(-3) 10 3 3 3 435 12.) =(15 9+10) (135 10) 145 217
2 2 2 2 2 23
1 13(- )-4( ) -1-1 123 43.) = 2 ( ) 24
1 1 1 1(- )( ) -3 4 12
Summary• The product of a number and ___ is 1.• Ans: reciprocal• Is dividing by a number the same as multiplying by the
opposite of the number? EXPLAIN your reasoning. • Ans: No, dividing is the same as multiplying by the
reciprocal• Is the reciprocal of a negative number sometimes, always or
never positive? • Ans: never• Describe the error shown below:
2 36 6 =9
3 2
Check Yourself
Pg. 106-108 #8-46e,59-60
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