Download Multiplicative Inverse

3.2 Solving Equations Using Multiplication & Division
Objectives
SWBAT:
• Solve simple linear equations using multiplication and division
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Multiplicative Inverse:
• Reciprocal (“flip”) of a number
Ex: the multiplicative inverse of 12 is 1/12 the multiplicative inverse of 1/3 is 3
• The product of a number and its multiplicative inverse is 1
Ex: 2 · 1 = 1
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Inverse Operations
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Using Inverse Operations to Solve Equations
GOAL: ISOLATE THE VARIABLE on one side of the equation
Examples:
1. Using multiplication 2. Using division
c = 15 4 n = 20
2 4 4
c · 2 = 15 · 2 n = 5
2 c = 30
3. Multiplying each side by a reciprocal
10 = ­2/3 m
(­3/2) 10 = (­3/2) ­2/3 m
­15 = m
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Properties of Equality
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Practice
Solve the equation:
1. 21 x = 7
2. ­10 x = ­9
3. x = ­20
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4. ¾ t = | ­15 |
5. 1/3 y = 5 2/3
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HW
p. 142 # 20, 22, 31 – 47 (odd)
p. 143 # 54, 58, 59, 60, 61 7
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